INTERNATIONAL LABOUR OFFICE

STUDIES AND REPORTS
Series F (Industrial Hygiene) No. 14

STANDARD CODE
OF

INDUSTRIAL HYGIENE

GENEVA
1934
Published in the United Kingdom
For

the INTERNATIONAL LABOUR OFFICE (LEAGUE OF NATIONS)

By P. S. KING & SON, Ltd.
Orchard House, 14 Great Smith Street, Westminster, London, S.W.I

k

k

Printed in Great Britain by
E Y R E AND SPOTTISWOODE L I M I T E D

His Majesty's Printers
'¿last Harding Street, London, E.C.4

CONTENTS
PJUÎFACE

STANDARD C O D E OF INDUSTRIAL H Y G I E N E

1.
2.
3.
4.

Working Premises Situated a t and above Ground Level ...
Workrooms Situated below the Level of the Surrounding Ground
Work under Shelters, Penthouses, etc.
Unhealthy or Offensive Trades

EXPLANATORY N O T I C E

1.
2.
3.
4.

Working Premises Situated a t and above Ground Level ...
Workrooms Situated below the Level of the Surrounding Ground
Work under Shelters, Penthouses, etc.
Unhealthy or Offensive Trades

G 9591

A

PREFACE
to the programme drawn up by the International
Labour Conference at its First Session in Washington in 1919, the
International Labour Office was instructed to pursue the task
of protecting the workers' health, with which it was entrusted
under Part X I I I of the Treaty of Versailles, first of all by
recommending suitable measures for safeguarding the health of
workers whose occupations exposed them to specific dangers.
The Office therefore undertook in the first place the study of
special problems, such as those of industrial anthrax, the
regulation of the use of white lead in painting, etc.
But however urgent and important this work might be, it did
not absolve the Office from the duty of considering also the lot
of those millions of workers employed in factories, workshops or
offices, who, without incurring specific risks, are nevertheless
exposed to all the dangers to health involved in unhygienic
conditions of work. For this reason the Office has judged it
important to engage without further delay in the study of
problems of industrial hygiene from a more general aspect,
both in the interests of the health of the workers and with a
view to the improvement of production and the furtherance of
social progress.
There is ample evidence that it was right in committing itself
to such a course. Several countries have established committees
of experts to bring up to date their industrial hygiene regulations,
and recently the American Standards Association framed, under
the auspices of the United States Public Health Service, a health
code for industrial establishments (November 1933), which is
about to be published.
Such is the justification of the standards presented in this
volume. Without losing sight of the numerous climatic, political
and economic differences between countries, the International
Labour Office has sought to set forth in outline those principles
on which any system of general regulation of industrial hygiene
should be based.
The object has not been to produce a document which might
serve as a basis for international Conventions or Recommendations, nor a standard system of regulations which the Office might
submit to the States Members of the International Labour

ACCORDING

6

STANDARD CODE OF INDUSTRIAL HYGIENE

Organisations in the hope that it might be adopted in its entirety.
The purpose of the Office has rather been to focus opinion on
rules which, in each State, might inspire either new measures or
the amendment of existing provisions, and also serve as a guide
for those concerned with the health of the workers. This volume
is a summary of the results of the experience of certain industrial
countries, supplemented by an explanatory note dealing with
the scientific and practical aspects of the subjects considered.
The original text, which was drafted on the basis of information collected by the Office, was discussed by the Correspondence
Committee on Industrial Hygiene, which appointed a small subcommittee for the drafting of the final text.
The Governing Body of the International Labour Office, a t its
Fifty-fifth Session (October 1931), adopted a resolution asking
that the Standard Code of Industrial Hygiene be submitted to
it before publication. This was done, and in consequence of
various criticisms of the text and suggestions for improvements,
the Office referred it yet again to the Correspondence Committee
on Industrial Hygiene. During its session held in July 1933
this body requested a sub-committee to consider the final form
to be given to the text. The final text so prepared was submitted
to a plenary meeting of the Committee, which approved it by a
majority vote.
All useful suggestions will be welcome by the Office and will
be duly submitted to the Correspondence Committee on Industrial
Hygiene.
Contrary to original intention, it has proved impossible, for
reasons of economy, to provide illustrations for the passages
dealing with various installations. 1

1
I n the absence of illustrations, readers are recommended to consult on this
subject the German publication constituting the 49th special number of the
Reichsarbeitsblatt, for an article b y Professor Waffenschmidt on sanitary
installations in factories and industrial establishments, or the following
publications of the British Home Office : Messrootns and Canteens at Small
Factories and Workshops (Welfare Pamphlet No. 2), 1931, 3rd ed. ; and Cloakrooms,
Washing Facilities, Drinking Water and Sanitary Accommodation in Factories
and Workshops (Welfare Pamphlet No. 8), 1933, 3rd ed. ; Ventilation of Factories
and Workshops (Welfare Pamphlet No. 5), 1933, 2nd ed. ; Lighting in Factories
and Workshops (Welfare Pamphlet No. 7), 1930, 3rd ed. ; and Welfare and
Welfare Supervision in Factories (Welfare Pamphlet No. 3), 1931, 2nd ed.;
all published b y H.M. Stationery Office, London.

CODE OF INDUSTRIAL HYGIENE
1.—WORKING PREMISES SITUATED AT AND ABOVE
GROUND LEVEL

I
Notification
In industrial and commercial establishments, all workrooms
in which workers are engaged irrespective of their number
should be made the subject of a notification. The notification
should contain a description of the work engaged in, and whenever
the type of work carried out changes a new notification should
be required.
II
Responsibility
Employers or their representatives should be responsible for
health conditions in working premises.
Ill
Posting of Notices
A notice should be posted in all working premises indicating
the duties of employers and workers.
IV
Height
In new constructions, in which workers are more or less
permanently employed, the height of the workrooms should be
at least 3 metres (9 ft. 10 in.). Exceptions to this rule should
not be admitted except on grounds of technical necessity.
V
Cubic Space
The cubic space of workrooms should be such as to afford,
without deduction for benches, machines, furniture and material,
at least 10 cubic metres per worker.
The calculation of cubic space may be based on the requirement of an area of 2 square metres (21-53 sq. ft.) per person,
but in this calculation height exceeding 4 metres (13 ft. 1£ in.)
should not be taken into consideration.
Compliance as regards cubic space does not obviate the need
for adequate ventilation of the workroom.

8

STANDARD CODE OF INDUSTRIA!, H Y G I E N E

VI
Area
The area of working places should be such that any worker
employed therein has sufficient space to move about freely.
VII

Roofing
Roofing on working premises should be constructed so as to
afford effective protection for the workers against heat or the
inclemency of the weather.
VIII
Walls and, Ceilings
Walls and ceilings in workrooms should have a surface
Avhich can be whitewashed or painted.
Walls should be proof against dampness, whether it
originates in the ground, in weather conditions or in the presence
of contiguous reservoirs.
IX
Flooring
Flooring or paving in covered-in working premises should
be solid, watertight, even and not slippery. The material of
which it is made should be easily cleansed.
In workrooms in which the processes carried on involve
wet flooring, it should, in the absence of other protection for
the worker, be such as to protect the workers' feet against damp
and loss of heat.
X
Apertures, Windows, Doors
In new constructions glass partitions, windows and other
external openings intended for the admission of light should
be of such dimensions t h a t their area amounts to at least onesixth of the area of the floor of the workroom. In calculating
this area, openings of sheds, roof lanterns, etc., but not glass
panes or partitions in inside doors, should be taken into account.
Windows and other sources of admission of light should be
so placed as to afford the most uniform distribution possible
of daylight in all parts of the workroom. They should be
easily cleaned. Some of them should be made to open readily.

STANDARD CODE 01? INDUSTRIAL

HYGIENE

9

XI
Measures should be taken to prevent direct radiation of
sun on to the workers, or over-heating of the workrooms, and
to prevent work being carried on in direct draughts.
XII
Where windows are the only means of natural lighting the
space between these and the ground should not exceed 1 metre
(3 ft. 3 in.). They should be so placed as to allow daylight
to fall on the opposite wall of the workroom.
XIII.
Doors should be well fitting and should open outwards.
XIV
Cleanliness and

Maintenance

Walls and ceilings should always be maintained in a proper
state of repair and of cleanliness.
The workroom should be cleaned as often as required by the
nature of the work carried on, and cleaning should preferably
be done during intervals between work and in a manner
calculated to prevent the raising of dust.
Special precautions should be taken wherever, for technical
reasons, cleaning must inevitably be done during working hours.
XV
Besidues, Waste Water
Residual matter, residues and sweepings and in general
waste material capable of harmful effects should be removed
daily from the workroom.
Measures should be taken to ensure effective removal of
waste water. This should be done in such a manner as to
obviate production of effluvia. Consequently, sewers should be
provided with hydraulic syphons or other effective devices
constantly maintained in good working order and repair.
XVI
Ventilation
Workrooms should be thoroughly ventilated at least once
daily outside working hours.

10

STANDARD CODE OF I N D U S T R I A L

HYGIENE

XVII
Lighting
I t is advisable t h a t all workrooms should receive adequate
natural daylight.
At the level of the working place the amount of light should
suffice for the accomplishment of the work without injury to
the workers' sight.
XVIII
Windows and roof lighting and also transparent parts of
artificial light sources should be kept sufficiently clean in order
that they may normally fulfil their function.

XIX
Artificial light sources should not cause overheating or
vitiation of the atmosphere; heat liberated by these should
not be permitted to constitute a source of discomfort for the
workers.
I n all circumstances these light sources should afford fighting
of practically constant intensity. Measures should be taken to
prevent glare and the production of troublesome shadows.
XX
Temperature
A temperature suitable to the work engaged in should be
maintained in the workroom. I n summer, workrooms should
be protected as far as possible against an excessive rise in
temperature. During the cold season workrooms should be
heated and a minimum temperature maintained. A thermometer
in good working order and readily accessible should be fixed
at the level of the workers' heads in the part of the workroom
furthest removed from the heating.
The workers should be protected against excessive radiation
from heating apparatus.
Heating apparatus should be so constructed as to prevent
contamination of the air in the workrooms.
XXI
Drinking Water
Good drinking water, or in default of this wholesome
beverages, should be provided for the workers. Distribution
should be effected under conditions conforming to hygienic

STANDARD CODE OF INDUSTRIAL HYGIENE

11

principles. Water supply intended for drinking should be legibly
marked " Drinking water."
XXII
Cleanliness
Adequate cloakroom and sanitary installations should be
provided and maintained in a good state of repair, enabhng the
workers :
(a) to keep their clothing, taken off during working hours,
under satisfactory conditions as regards safety 1 and health ;
(6) to wash then- faces and hands.
XXIII
Seats
Seats should be provided for all workers obliged to work
in a standing position, in order t h a t they may profit by any
opportunities for rest which may occur during the course of
their work.
XXIV
Spittoons
Notices explicitly forbidding spitting on the floor should
be posted in all workrooms and adjacent premises. Where it
is found necessary to provide spittoons they should be sufficient
in number and so made and maintained as to satisfy hygienic
requirements.
XXV
Privies, well constructed, separate for men and women, and
in sufficient number, should be provided for the workers, their
situation being clearly indicated.
Privies for men should comprise urinals.
Privies should not be in direct communication with the
workrooms; they should be kept clean and thoroughly cleaned
at least once daily. They should be adequately lighted and
ventilated.
Construction and maintenance of the installations and
emptying of cesspools, where such exist, should conform to
hygienic requirements. The same applies to drains.
1

Against theft.

12

STANDARD CODE OF I N D U S T R I A L

HYGIENE

2.—WORKROOMS SITUATED BELOW T H E L E V E L
T H E SURROUNDING GROUND

OF

XXVI
Semi- Underground Premises
Where the competent authority deems it necessary to
permit work being carried on in semi-underground premises
all the foregoing provisions relative to notification, responsibility,
posting of notices and work applicable to workrooms situated
at or above ground level should likewise apply to workrooms
the flooring of which is below the level of the outside ground.
The walls and flooring, after being thoroughly dried, should
be covered with a damp-resisting material.
XXVII
In addition to the foregoing provisions, underground work
should be subjected to special restrictions laid down by the
competent authority.
3.—WORK U N D E R S H E L T E R S , PENTHOUSES, ETC.
Flooring, Lighting, Drinking-Water,
Cleanliness,
Spittoons, Privies
XXVIII
The provisions in paragraphs I X , X I X , X X I , X X I I , X X I I I ,
X X I V and XXV, in so far as they are practicable, should
apply to work under shelters, penthouses, etc.

XXIX
Roofing
Roofing, screening, etc., should be such as to guarantee
effective protection for the workers against the heat of the sun
and the inclemency of the weather.
4.—UNHEALTHY OR OFFENSIVE T R A D E S
XXX
General

Provisions

All the provisions relative to work not involving special
health risk should also apply to unhealthy or offensive trades.

STANDARD CODE OF INDUSTRIAL HYGIENE

13

XXXI
Special Provisions
I n the absence of provisions included in special equivalent
regulations, this work should be subject to the following provisions, in accordance with the nature of the risk involved.
XXXII
Dampness, Steam,

Vapour

In workrooms in which the work carried on is the direct cause
of abnormal humidification of the atmosphere :—
(a) the temperature should not be under 15° C. (59° F.), nor
over 25° C. (77° F.) wet bulb, except, as regards the latter,
where the outside temperature is still higher;
(6) measures should be taken to protect the workers from the
eflects of condensation of steam ;
(c) hoods with ducts or other methods should be adopted for
the suppression of steam.
XXXIII
Humidificatio7i
Where there is artificial and intentional humidification of the
atmosphere of the workrooms, there should be provided in each
workroom a special hygrometer, calibrated and situated close
to the working places.
Readings of these should be noted daily a t least one hour after
beginning and at most one hour before the end of the working
shift. These readings should be recorded and kept at the disposal
of the competent authority.
XXXIV
Artificial humidification should be prohibited whenever :—
(a) the wet bulb thermometer registers 25° C. (77° F.) ;
(6) the difference between the two thermometers is under
1-5°C. (2-7° F.).
XXXV
Water used for humidification, pulverisation or spraying
should be taken from a source known to be free from any risk as
regards health.

14

STANDARD CODE OF INDTTSTBIAL HYGIENE

XXXVI
Irritant Toxic or Asphyxiating Smoke, Fumes and Oases
Escape of irritant toxic or asphyxiating smoke, fumes or gas
in workrooms or adjoining premises should be prohibited. Production and diffusion of smoke, fumes and gas of this nature
should be proliibited as far as possible and their removal should
be ensured by exhaust ventilation installed as near as possible to
the point of production. Such smoke, fumes and gas should be
rendered harmless prior to being passed into the outside air.
XXXVII
I n workrooms in which, in spite of all precautions taken,
asphyxiating toxic or irritant fumes and gas may escape, the air
renewal should be such t h a t the workers' health does not suffer.
XXXVIII
No worker should be allowed to enter without protective
apparatus places likely to contain toxic asphyxiating, or inflammable fumes or gas, until it has been ascertained t h a t there is no
risk.
During work in closed apparatus and enclosed or partially
enclosed spaces, where there is reason to apprehend the presence
of dangerous gas or fume or an irrespirable atmosphere, approved
masks or oxygen breathing apparatus should be provided and
worn by the workers. Safety belts with ropes attached should
also be provided and used, and wherever possible at least one
person should supervise from the outside the worker or workers
exposed to danger.
XXXIX
Dust
Escape of dust in workrooms or adjacent premises should be
avoided. During manipulation of dust-producing material, or
manual or mechanical work causing dust liable to injure the
health, requisite measures should be taken to prevent dispersion
of such dust in the air of the workroom.
XL
Mechanical processes accompanied by liberation of dust
should as far as possible be carried on in closed apparatus, provided
with exhaust devices.

STANDARD CODE OF INDUSTRIAL HYGIENE

15

In default of such methods, localised exhaust hoods should be
provided to capture the dust as close to its point of origin as
possible.
Dust collected should be rendered inoffensive or
destroyed.
XLI
In dusty trades, cloakrooms, washing accommodation, and
eventually douche-baths, separate from the workrooms, should be
provided for the workers. Conditions in regard thereto should be
laid down by the competent authority.
XLII
Large Furnaces
In industries or trades where the nature of the work necessitates the use of glowing furnaces, measures should be taken to
prevent workers in other departments of the establishment from
being exposed to their action.
XLIII
Fireproof screens for protection from heat and, where necessary, fireproof suits or articles of clothing, and also glasses affording
protection against harmful radiation, should be placed at the
disposal of the workers directly exposed.
XLIV
Air renewal in workrooms should be such that high temperature does not injure the workers' health.
XLV
Drying-Rooms, Stoves
At no season should workers be made to enter drying-rooms
and stoves when the interior temperature of these exceeds 50° C.
(122° F.). Remaining in them continuously should be prohibited
when the temperature exceeds 35° C. (95-O0 F.).
XLVI
Noise, Vibration, Shocks
In noisy trades and in those in which the running of machinery
causes noise, shocks and marked vibration, every effort should be
made to reduce as far as possible the disagreeable effects.

16

STANDARD CODE OF INDUSTRIAL HYGIENE

Poisons
Any industrial or occupational operation involving manipulation, manufacture or use of, or causing production of, toxic
substances should be subject to the following restrictions :—
(a) apparatus to remove and render harmless gas, fumes or
dust containing poisons should be installed with the greatest
care and maintained in perfect working order ;
(6) the competent authority should specify in each particular
case the requisite technical measures of prevention to be
taken, the number and arrangement of lavatories, douchebaths with their accessories, and the working clothes and
articles of personal protection to be worn and maintained ;
(c) the introduction, preparation and consumption of food in
the workroom should be prohibited. Meals should be taken
either in a canteen installed and maintained in a satisfactory
condition for the workers, and heated in the cold season, or
outside the factory ;
(d) periodical medical examination of the workers should be
organised, and the workers should be informed of the risk
they incur, and of the precautions to be taken with a view
to avoiding it.

EXPLANATORY

NOTICE

1.—WORKING PREMISES SITUATED
GROUND L E V E L

AT AND ABOVE

I
Notification
By the term " working premises situated at and above ground
level " is meant every type of industrial and commercial establishment without distinction, and apart from any question whatsoever of particularly unhealthy or offensive work. There is
therefore no intention of defining here industrial or other work
of this kind, nor of specifying the types of factories or industrial
establishments covered. What is of importance is that it should
be clearly understood that all provisions contained in the first
part of this Standard Code are applicable to all work carried on
in any working premises whatever.
I t is a question of establishing minimum standards which
require to be adopted with a view to issuing measures intended to
serve as a basis for hygienic working conditions in new establishments, and it is with this in view that the paragraph relative to
notification was drafted in the most general manner possible.
Renewal of the notification referred to in the text of the
Standard Code is of importance with a view to preventing possible
abuse when for instance an establishment hitherto destined for
work free from risk becomes utilised for work involving dangerous
processes without notice given to the competent authority
regarding this change.
II
Responsibility
I n the problem under consideration it is evident t h a t the
question is one of the responsibility of an employer or his representative. However, under certain circumstances and in certain
countries, notably in Great Britain, there exist legal provisions
in virtue of which the proprietor of a factory, whether or not he
manages the latter, is responsible for the application of measures
of hygiene concerned with the construction and plant. As an
instance may be quoted the case of establishments in which motor
power is distributed in the different parts of a building occupied
by various persons, each of them carrying on a different occupation
(tenement factories).
a iinoi

li

18

STANDARD CODE OF INDUSTRIAL HYGIENE

III
Posting of Notices
The objection has been made that posting up of notices would
constitute a useless measure since the majority, if not all, of the
workers do not read such notices. I t is nevertheless true t h a t the
omission of such a measure prevents those who might have the
intention of profiting by it from becoming acquainted with
information relative to their rights and their duties.
The notices in question generally contain the texts of the
hygiene regulations. They should be printed in legible characters
and posted in a prominent place, for instance near the entrance
through which all the workers are obliged to pass. I t might be
advisable, perhaps, to increase the attraction of such posters by
providing them with illustrations. The number of notices posted
up should, however, be reduced to a strict minimum, since where
these are unduly numerous the effect achieved is exactly contrary
to t h a t intended.
I n certain cases—besides hygiene regulations—special notioes
are posted indicating for each workshop : (a) the height, length
and breadth of the room ; (6) the cubic space ; (c) the number of
workers t h a t may be employed. Further, where appropriate, it
would be possible to inform the workers by means of such notices
of the dates of medical examinations and of the precautions
to be adopted against the dangers inherent in certain processes.
Here it is naturally a question of the industries covered by the
fourth part of the Standard Code, t h a t is to say, those involving
processes which are specially unhealthy and offensive (see below).
IV
Situation
Provisions concerned with the situation of industrial constructions are in general contained in public health regulations
relative to buildings. I n this case the principal consideration is
that of measures calculated to safeguard health in the neighbourhood, and the question of industrial hygiene properly so-called
is but a secondary consideration.
In the text of the Standard Code there is no allusion to the
site or situation of the factory. This omission is justified by
the fact that the measures in view are intended to apply to
every type of establishment and in consequence even to premises
situated, for instance, on damp and marshy soil. I t is an under-

0
STANDARD CODE OF INDUSTRIAL H Y G I E N E

19

stood fact, of course, t h a t once a previously constructed edifice is
in question every measure should be taken to protect the latter
against all conditions which may prejudice the workers' health,
and which may be enumerated as follows : (1) dampness arising
from the ground or from outside; (2) changing temperature,
especially in winter, in buildings constructed of insufficiently solid
.material; (3) wind and rain. Finally, it is essential to consider
the question of exposure to sunlight in order to assure provision
of a sufficient quantity of daylight.
Height
In the majority of standard codes a fixed minimum limit of
height is given with a view to preventing the construction of
unduly low workrooms. It is, however, equally necessary to take
into consideration the maximum limit compatible with the best
working conditions. For this reason attempts have at times been
made to regulate the height of a workroom in relation to its
surface. The fact must not, however, be overlooked that in certain
instances an attempt to do so is likely to encounter technical
difficulties, as, for instance, in breweries or starch factories, where
workrooms with a large surface would by no means necessitate a
corresponding height. Such workrooms are very spacious, having
a t times 300 to 400 square metres (359 to 478 sq. yds.) of surface,
though very few workers are employed therein. The essential
point is to determine generally acceptable average heights, for,
though it may be in contradiction with the principles of hygiene
to accept standards of insufficient height in working premises, to
insist, on the other hand, on unduly high dimensions involves
demanding the immediate and final closing down of a great
number of establishments which are nevertheless acceptable.
For this reason there has been adopted a height of 3 metres
(9 ft. 10 in.). I t constitutes a dimension which satisfies the
psychological needs of the worker ; the welfare of the latter and
his contentment during working hours are to a large extent
dependent on the free space by which he is surrounded. The
height of the workroom must, however, be t h a t measured from
the ground to the top of the walls and not to the top of the roof,
which may be a sloping one and thus lead to a wrong estimate.
V
Cubic Space
The notion of cubic space is independent of the three dimensions which provide its definition. The section devoted thereto
B 2

20

STANDARD CODE OF INDTJSTBIAL HYGIENE

in the text of the Code does not in consequence in any wise render
superfluous the preceding one, for there may exist workrooms
(underground, ground floor, attics) which give perfect satisfaction
from the point of view of cubic space, but whicli nevertheless are
inadequate as regards height (often 1-80 metres (5 ft. 11 in.) and
even 1 • 50 metres (4 ft. 11 in.) ).
The cubic space in itself constitutes only an estimation of the
quantity of air available for each individual worker. I t should
in consequence be supplemented by the conception of air circulation with a view to providing a worker immobilised in a closed
room with the greatest possible quantity of air. Regarded from
this dynamic aspect, the rate which is considered to correspond
to the physiological needs of the human body under ordinary
conditions is about 30 cubic metres (40 cub. yds.) per worker and
per hour.
Nevertheless, as in the Standard Code, certain hygiene experts
currently employ a static definition, i.e. a fixed quantity of cubic
space, and it is of interest to recall here t h a t the German Association of Industrial Physicians has fixed the cubic space necessary
for a worker at 15 cubic metres (20 cub. yds.). There was,
perhaps, a certain element of opposition to the dynamic conception
of the cubic space, in the opinion expressed by those hygiene
experts who foresaw the possibility of a certain disadvantage t o
the workers' health in unduly intense air renewal, or rather who
stressed the workers' own fears as regards draughts. I t is evident
t h a t such counter-arguments do not, however, constitute fundamental and definite opposition but merely demand as occasion
arises the adoption of adequate technical measures to prevent
risks of this kind. In estimating the quantity of air required for
each worker it is essential to take into consideration, in fixing the
requisite cubic space, the character of the work engaged in
(sedentary work, work involving movement, slow, rapid, etc.). 1
The great difficulty which arises in connection with the problem
of cubic space is that of control of air renewal by inspectorates.
One of the methods indicated is t h a t of estimating the carbonic
acid content of the air in the workrooms. The methods involved
in such estimation, however, are cumbersome for inspectors, and
the analyses required demand extremely delicate interpretation
according to the spot at which the air sample has been taken.
1
Modern technique enables the same results to be obtained from the use of a
single appliance for air conditioning (filtering, cleaning, renewing, humidifying,
heating, etc.).

STANDARD CODE OF INDUSTRIAL H Y G I E N E

21

Another method consists in the use of the katathermometer, but
the objection which has been raised against the practical efficiency
of this instrument is that it indicates merely the air renewal and
not the chemical composition of the air.
VI
Area
Like the height of the workroom, the surface also presents an
aspect of particular importance. Thus, where workers are obliged
to execute their work at working posts situated opposite each
other, a certain separation ensures avoidance of the danger of
transmission of contagious diseases, and especially tuberculosis.
On the other hand, as in the case of height, the psychic factor
enters into consideration and the impression of liberty of movement experienced by the worker when provided with sufficient
space contributes to his contentment, especially where it is a case
of work carried on under relatively trying conditions from other
points of view (for instance, in underground or attic premises).
The figure of 2 square metres (2-39 sq. yds.) per worker, as
specified, for instance, by the Austrian and Italian regulations,
may be considered as a satisfactory minimum.
VII
Roofing
As regards the construction of various kinds of roofs, the health
of the workers may be prejudiced by failing to take into consideration the following factors : draughts and lowering of temperature
due to permeable or defectively constructed roofing material, the
accumulation of evaporation products and humidity in workrooms with a flat roof, penetration of rain or snow where the roof
is not absolutely watertight, diminution of lighting where lighting
apertures in the roof are inconveniently situated. I t follows therefore that the attention of hygiene authorities should be directed
to these various points when elaborating conditions to be fulfilled by factory roofing constructed in accordance with requirements. There are at the present time in existence different types
of roofing adopted for industrial construction. The best known
are : sheds, or saw-tooth roofing, span roofing, arch-shaped roofs
and skylights.

22

STANDARD CODE OF I N D U S T R I A L

HYGIENE

VIII
Walls and Ceilings
I n the case of enclosed workrooms the walls and ceilings should
satisfy certain hygienic requirements. There should notably be
taken into account the following considerations :
Humidity.—Since humidity generally arises from the ground,
it is advisable t o prevent it by means of insulation devices, in
addition to taking measures for improving the ground;
where it is a question of humidity necessarily resulting from the
type of production, it is advisable t h a t the walls should be
covered with cement or similar material.
Dust.—In order that dust produced should be rendered
readily visible, oil painting of the walls in a light colour is advisable. Oil painting is likewise advisable in order to facilitate ready
cleansing of the walls. I t may be replaced by whitewash or in
certain particular cases by papering with washable paper.
Temperature.—The walls should be of sufficient thickness to
ensure, where essential, satisfactory insulation against the influence
of the external temperature.
Light.—The walls should preferably be light in colour with
a view to augmenting, if need be, the lighting capacity of the
windows.
IX
Flooring
From the point of view of the workers' health, the flooring
should be so constructed as to prevent : emanations and dampness from the ground, the accumulation of dust and other waste
material in grooves or fissures of the flooring during work or
cleaning.
The type of work engaged in must determine the choice of
material for the construction of the flooring. Three general types
of occupation may be distinguished according to the attitude of
the worker : first, work during which the worker remains seated
at a certain place ; secondly, work during which he moves within
a small radius around the working post, and, finally, work during
which the worker is obliged to move about the workroom. I n
an establishment where workers remain seated, the flooring should
be thick and warm, since special exposure to cold is involved in
this case. The same holds good for the class of workers restricted

STANDARD CODE OF INDUSTRIAL HYGIENE

23

to movements within a small radius. As regards the third class of
workers, the type of flooring demanded for the two previous
classes becomes less important. On the other hand, in this last
case, it is advisable to avoid slippery flooring, not only on account
of accidents but also with a view to preventing fatigue caused by
moving about under such conditions.

X, X I , X I I and X I I I
Apertures,

Windows, Doors

The apertures which are of importance from the point of view
of industrial hygiene are windows, since they assure provision of
daylight.
In constructing the windows there must be taken into consideration requirements as regard daylight, prevention of draughts
and undue cooling of the workroom. The dimension of the
windows is of great importance from the point of view of adequate
provision of daylight. I t is recognised that to obtain adequate
daylight their total surface should equal on an average at least
one-sixth of the surface of the floor. The height of the window
is more important than its breadth and the space between the
top of the window and the ceiling should be as small as possible.
This gives at the same time a larger angle of incidence for the
light. These conditions constitute the basis of the Standard
Code in so far as it relates to the construction of windows, and
the figures quoted therein represent optimum conditions.
Finally, as regards the psychological aspect, it is desirable t h a t
even in workrooms where daylight is provided from above (sheds)
windows should be provided in the walls to combat the feeling
of isolation and imprisonment which is inspired by a walled
building without windows.
XIV
Cleanliness and Maintenance
The question of effecting cleaning outside working hours is
still engaging the attention of hygiene experts. The main
consideration is to protect workers against inhalation of dust
which may be raised during cleaning, especially where the latter
is effected by primitive methods. Where possible it is advisable
to utilise the period immediately following the cessation of

24

STANDARD CODE OF INDUSTRIAL HYGIENE

work and not that which precedes the commencement of work,
or even short intervals during which interruptions of work
occur. I t is only under special circumstances, notably in
continuous processes, t h a t it becomes impossible to follow such
methods, and in the latter case cleaning has to be effected during
work. I t is true that at the present time, with the technical
methods available which permit of cleaning without raising dust
in the Avorkroom, the question of cleaning during or after working
hours has become one of minor importance. However, these
considerations at once assume importance again whenever
precautions for preventing dust production (vacuum cleaners,
etc.) are omitted.
A distinction must further be made between cleaning, that is
to say, thorough cleaning, and simply dusting, or surface cleaning.
It may be possible to admit of the latter being effected during
working hours, but where it involves the raising of dust to a
similar extent as in the case of thorough cleaning, the choice of
time for effecting it must depend entirely on the means with
which it is effected. On the other hand, effecting thorough
cleaning during working hours, even where means are applied
to prevent dust production, meets with considerable obstacles
since it involves grave interference with the workers.
XV
Residues, Waste Waters
The removal of refuse, residues, sweepings and in general all
waste matter is essential in virtue of the fundamental principles
of hygiene. Even where the refuse in question is not likely to
give rise to injury to health, as, for example, in the case of metal
clippings in engineering workrooms, the presence of these becomes
a serious inconvenience and favours accumulation of products
likely to prejudice the health of the workers. Moreover, they
constitute an encumbrance for the worker, already but too little
concerned with considerations of order and cleanliness, and
eventually create for him a sense of discomfort likely to be
reflected by a diminution in his welfare and contentment and
finally in his capacity for production.
As regards waste waters, their removal should be effected in
such a manner that their dispersal in the workrooms or in the
neighbourhood of the factory is prevented.

STANDARD CODE OF INDUSTRIAL H Y G I E N E

25

XVI
Ventilation
Natural airing of the workrooms is effected by means of
doors and windows and in less degree through the interior walls.
Circulation of air is determined by the difference between the
temperature of the air of the workroom and that of the air in
the adjoining atmosphere as Avell as by draughts (wind).
Under ordinary conditions, air renewal takes place in this
manner once per hour or once in two hours, which means t h a t
airing is inadequate. I t requires to be supplemented either by
opening the windows or by the provision of artificial ventilation.
When windows are opened during working hours, efforts must
be made to avoid the production of draughts arriving directly at
the working posts. I t is generally sufficient to open that part of
the windows which is above the level of the workers' heads and
assure protection by screening the sides of the angle formed by
the windows which open from top to bottom. Very frequently
this kind of ventilation is overlooked owing to the fear of draughts,
or in the absence of suitable devices permitting of regulating the
opening of windows without difficulty.
During interruptions of work wholesale ventilation should
take place by opening doors and windows opposite each other.
Under these conditions complete air renewal is effected in two
to five minutes.
I n numerous cases natural ventilation is inadequate, and in
such circumstances it is essential to have recourse to various
types of apparatus. Amongst ventilators without mechanical
movement should be mentioned air-pipes constructed in the
walls, which, by reason of the difference between the temperature
of the interior and exterior atmosphere, give rise to atmospheric
circulation. These pipes generally start from the foot of the
wall, except where special conditions call for elimination of the
upper layers of the atmosphere of the workrooms. In order to
stimulate circulation, a current of air is injected or a flame is
lit in these pipes. The latter practice is, however, being gradually
abandoned. Air pipes may also be provided in the roof or near
the chimneys.
Mechanical ventilating apparatus is generally operated by
steam or by electricity. At the present time artificial ventilation
by mechanical means is being more and more applied, and in the

26

STANDARD CODE OF INDUSTRIAL HYGIENE

majority of modern factories there exist various types of such
apparatus for assuring air renewal. 1
XVII, X V I I I and X I X
Lighting
Lighting may in general be considered adequate when the
luminous intensity, that is to say, the quantity of light falling
on a unit of surface (1 square metre), is sufficient for executing
any kind of work. Apart from that, the lighting intensity
should not be subject t o considerable and repeated oscillations
and particularly those occurring at fixed intervals. Finally,
the eye should not be fatigued by an unduly intense glare from
the lighting source nor by violent contrasts.
The luminous source used may be either natural or artificial.
Natural lighting.—Natural lighting is that provided by solar
radiation, in other words, daylight. This type of lighting is
extremely variable and is influenced chiefly by the season, the
hour of the day, meteorological conditions, and the extent of sky
visible from the building. The brightness of the sky varies
greatly in accordance with meteorological conditions and it is
greater when the sky is not blue.
At present new factory constructions receive a fairly well
regulated amount of daylight distributed by large apertures in
the roof (sheds, skylights) or in the case—the most usual—of
buildings of more than one storey, by glass walls. For top
lighting, the glass roof with a northern exposure has an angle
of 40 to 45 degrees on both sides or one side of the dihedral
angle which forms the roof. This top light is often used in
combination with lateral lighting.
Where lateral lighting is in question the extent of sky which
provides the light depends on the height of the window, provided
t h a t the situation of adjoining buildings does not interfere with
the access of daylight.
I n addition, account must be taken of the ratio existing
between the height and the width of the workroom, since it is
well known t h a t fighting is inversely proportioned to the square
of the distance which separates a given point from the wall in
which the window is placed. According to Nussbaum, the
1

See footnote, p . 20.

STANDARD CODE OF INDUSTRIAL

HYGIENE

27

respective values for height and width of a room should be as
follows -1
For a room of 4-00 metres in width
4-50
5-00
5-50
600
6-50
7-00

2 • 70 metres in heignt
3-00
3-30
3 • HO
3-00
4-20
4-50

As regards the working post, window panes, blinds, curtains,
the colour of the walls and ceiling, the colour of the outer walls
of the opposite building represent so many factors capable of
improving or otherwise the local conditions of lighting. Apart
from white more or less attenuated in shade, yellow is the colour
which provides the best luminosity, especially with artificial
hghting.
In order that natural fighting should be adequate, it must
fulfil the following conditions :
the light should arrive as far as possible a t the opposite wall
of the room ;
the light should arrive at the working post from the most
effective direction ;
the distribution of the light on the working post should be as
uniform as possible ;
the interior walls and furnishings of the workroom should be
of a colour and have a surface such that they only absorb
very little of the light falling on them ;
machines and accessory apparatus should be so placed as to
avoid causing any inconvenient shadows.
Artificial lighting.—As regards artificial lighting, the conditions to be fulfilled may be summarised under the following four
heads :
(1) the fight should be sufficiently intense ;
(2) the light should not be productive of disturbing contrasts ;
in consequence it should not form shadows capable of
interfering with the vision and should not be subject to
unequal distribution ;
(3) the lighting source should not be productive of glare ;
(4) the light should be economical.
1

2-70 m. = 8 ft. 10 in.
4-00 m. = 13 ft. 1 in.
7-00 m. = 22 ft. 11 in. •

28

STANDARD CODE OF INDUSTRIAL

HYGIENE

(1) There are given below the values, suggested by the
Illuminating Engineering Society of America and adopted by
the American Standards Association (September 1930), expressed
approximately in lux.
Work where there is no necessity to discriminate detail
...
(Manipulation of a coarse material ; grinding clay products ;
rough sorting ; coal and ash handling ; foundry charging.)
Work where slight discrimination of detail is essential
...
(Rough machining; rough assembling; rough bench w o r k ;
rough forging ; grain milling.)
Work where moderate discrimination of detail is essential ...
(Machining ; assembling ; bench work ; fine core making in
foundries.)
Work where close discrimination of detail is essential...
...
(Fine lathe work, pattern-making, tool-making; weaving
or sewing of silk or woollen textiles of light colour; office
work ; accounting ; typing. )
Work where discrimination of minute detail is essential
...
(Drafting ; weaving or sewing of dark coloured materials ;
very fine inspection or inspection of very dark goods.)

5 lux
10 lux
20 lux
40 lux

80 lux

In the same industry the lighting intensity varies according
to the process executed. There may be given as an instance of
this details relative to certain occupations :
Printinfj industries
Matrixing and casting
...
...
Proof reading, lithographing, etc.
Engraving
Cotton industry
Lapping, carding, dyeing, etc.
Spooling, spinning, etc.
Weaving, light goods
Weaving, dark goods
Knitting machines...

...

...
...

...
...

...
...

120/80 lux
150/100 lux
1,000 to 250 lux

...

...

...

80/50 lux
120/80 lux
120/80 lux
200/120 lux
150/100 lux

(2) The contrasts or shadows caused by artificial lighting
should not exceed a certain degree, constituting otherwise
inconvenience. However, a complete absence of contrasts or
tones in the lighting intensity is also harmful for the work, since
estimation of distance is hampered by this fact; while unduly
strong contrasts lead to faulty estimation as regards depth and
salient points, complete absence of these renders all estimation
impossible.
(3) I t is indispensable to avoid direct glare produced by the
light source.
Protection of the eye should be assured by a shade which
completely covers the source of light and concentrates the light
on the work at the point where it is most necessary. I t is further
essential to assure the best position of the source of light so t h a t

STANDARD CODE OF DÎDUSTKIAL

the eye is not hampered
surfaces on to which the
(4) In order to fulfil
should be so distributed

29

HYGIENE

by glare from the work or from brilliant
light is reflected.
the requirements of (4), sources of light
as to avoid waste.

XX
Temjwrature
I n order to determine temperatures for the workroom, it is
necessary first of all to take into account the type of work done
by the workers engaged therein. The aim must be to attain
an optimum temperature which, of course, would vary with the
nature of the work in question. In Belgium the following average
temperatures are generally permitted : x
Sedentary work ...
Light work
Work involving more movement

...
-...
...

Min.

Max.

15° C.
12° C.
10° C.

.1.8° C.
10° C.
12° C.

I n France, Lebrasseur (1909) and Maniguet have furnished
the following figures :
Sedentary work not demanding violent effort
(Lebrasseur) ...
Sedentary work demanding muscular effort
(Lebrasseur) ...
H a r d work (Lebrasseur)
AVorkrooms intended for workers moving
about, according to occupation (Maniguet)...
Workrooms for women at sedentary work
Shops
Offices

Min.

Max.

15° C.

20° C.

13° C.
10° C.

18° C.
15° C. winter

14°
18°
16°
17°

19° C.

C.
C.
C.
C.

—

17° C.
18° C.

I n Great Britain, Haldane and Osborne are of opinion that the
surrounding temperature should not fall below 00° F. (15-5°C),
especially in the case of light work executed by sedentary
workers.
Whenever the type of work effected permits of it, the
temperature of closed workrooms should be maintained within
limits approaching those indicated above.
I n summer the workrooms should be as far as possible protected
against excessive elevation of the temperature. Amongst other
means applied for this purpose, mention should be made of
ventilation of the workroom, painting of window panes in light
colours (bluish white), the playing of a water spray directing
fresh water over the roof, etc. A thermometer should be fixed
and maintained in good working order in each workshop. In
1

10" C. - 50. F .
20° C. • -- 08° F .

30

STANDARD CODE OF INDUSTRIAL HYGIENE

order to determine accurately a suitable temperature for the
workers, it is necessary to take into account the influence exercised
by the wet bulb and the air movement.
During the cold season, heating of the workrooms should be
adequately provided for. Heating apparatus should be provided
with devices ensuring regular elimination of combustion gases.
The use of keys and regulating dampers hable to close completely
piping for evacuation of these gases should be prohibited. Finally,
stoves and piping belonging to the heating system should be so
installed t h a t the workers do not suffer from heat radiation or
circulation of hot air.
Heating, air movement and ventilation of the workrooms
should be so arranged as to correspond and combine satisfactorily.
There may be distinguished amongst various types of heating,
local heating (fireplaces, braziers, stoves) and central heating.
The latter tends increasingly to replace the former type. Amongst
systems of central heating may be distinguished heating by hot
air—the oldest system, which is falling more and more into
disuse—and central heating by means of water or steam, the
latter at high or low pressure. There is finally the system of
heating by radiation, by means of heated panels (used chiefly
in offices).
The heated air provided for the workrooms may be partly
utilised again after undergoing purification (ozonisation, etc.).
XXI
Drinking

Water

The existence of a good provision of drinking water is of special
importance from the health point of view. Amongst devices for
this purpose, two types may be distinguished : one by means of
which the workers drink from a water jet, playing in an upward
direction, whilst the other involves the use of cups. The former is
obviously preferable, since it eliminates possibility of contagion
due to the use by several people of the same cup.
XXII
Cleanliness
In the text of the Code, amongst the means necessary to the
workers for fulfilling the requirements of bodily cleanliness,
mention has been made of :
(a) cloakrooms;
(6) provision of lavatories.

STANDARD CODE OF INDUSTRIAL HYGIENE

31

(a) Cloakrooms.—In small factories and workshops a simple
collection of pegs for hanging clothes is usually placed at the
disposal of the workers. In this case it is essential that each
worker should have a special place reserved for his own use and
bearing his name or a number. The distance between the
various pegs should not be less than 50 centimetres (19-7 in.),
so as to avoid contact of wearing apparel belonging to different
workers. Under these conditions " safety " (the term " safety "
used in the text of the Code refers to safety against theft, not
a t all to safety against accidents) is not always assured and
often the workers refuse to leave their town clothes in such a
place. Control of access to cloakrooms where clothes are left,
or other arrangements of a special character, may obviate this
disadvantage. Such arrangements consist in : (1) suspension
of the clothes at a height which is directly inaccessible but which
may be regulated from below; (2) the provision of individual
lockers. Such lockers have dimensions varying between
30X30X180
centimetres
(11-8 X 11-8 X 70-1 in.) and
40 X 40 X 200 centimetres (15-7 X 15-7 X 78-7 in.). They are,
as a rule, divided into two compartments, the upper for the
h a t and the lower for clothes, shoes, etc.
The cloakroom should be outside the workrooms and should
be spacious and well ventilated. I t should contain benches
where it is necessary for workers to change their trousers or
shoes in order that they may be comfortably seated while
doing so.
In large undertakings special arrangements are provided
permitting of the drying of working clothes or of town clothes
after rain. I n general, installations are provided with radiators
placed below the hanging apparel or below individual lockers.
Effective ventilation should in such cases be applied to assure
withdrawal of the steam produced.
Rooms intended as cloakrooms should be maintained in a
state of rigorous cleanliness. They should further be situated
near the lavatories.
(b) Lavatories.—As regards the requisite means for the
washing of hands and faces, the most important consideration is
to have simple and easily cleaned installations constructed of
resistant and hard-wearing material and provided in sufficient
number to permit of all the workers using them with loss of
the least possible time. A certain proportion between the number

32

STANDARD CODE OF I N D U S T R I A L

HYGIENK

of wash basins and the number of workers employed should be
observed, the average figure being usually one wash basin for
every five workers.
The lavatories should be provided with running hot and
cold water and a system of waste pipes for the withdrawal of
used water. When the lavatory is intended for several workers,
the distance between the water pipes should be sufficient to
prevent the workers getting in each other's way.
In any case, the pipes should be fixed at a convenient height
(50-80 centimetres) (19-7-31-5 in.) above the individual or
collective wash-basins, enabling the worker to wash his face
and chest at the pipe. The type of basins ' which fulfil the
requirement most satisfactorily are those made of enamelled
cast metal.
The workers should besides be provided Math all requisite
toilet accessories.
With a view to preventing disappearance of toilet accessories,
nail brushes should be attached by means of small chains or even
screwed on to the basin in a position permitting their ready use.
Liquid soap may be provided in distributors fixed to the wash
basins or near them, and towels may be fixed on a locked support.
I t is preferable that each worker should have an individual towel
which he can, if necessary, keep in his locker. Possible transmission of infectious diseases, skin infections, etc., is thereby
avoided. Roller towels are nevertheless .commonly used, though
it is earnestly hoped t h a t this practice will soon be abandoned.
The flooring of the lavatories should be impermeable and easily
cleaned ; likewise the walls up to a height of 1 • 20 to 1-50 metres
(47 to 59 in.), unless the wash basins are situated in the middle
of the room or at a sufficient distance from the walls. The best
means of protecting the floor and the exposed part of the walls
consists of tiling similar to that used for bathrooms.
XXIII
Seats
The question of seats is at present engaging the attention of
the majority of industrial hygiene experts. I n this connection
it is interesting to note that the German Industrial Hygiene
Association has published the following suggestions drawn up
by the Committee for Health Organisation in Industry.
(t) Work executed standing usually demands greater effort than that
effected in a sitting posture ; in consequence, despite the fact that all

33

STANDARD CODE OF INDUSTRIAL HYGIENE

operations cannot be effected sitting, all those concerned should devote
their attention to ascertaining whether a great number of operations
effected by workers standing, in accordance with tradition, cannot be
completely or partially effected by sedentary workers.
(2) Physiological research has proved that certain work—for instance,
pulling of weights and, what is somewhat similar, traction by cranking—
can be effected with much less effort seated than standing. For lifting
weights or propulsion by cranking the standing position is, on the other
hand, preferable.
(3) For work effected sitting it is very important that the lumbar
region should have a good support. Research effected with the aid of
the cinema on naked subjects has demonstrated that in the sitting position
it is not only the thoracic region of the back which is bent forward
but that the anterior convexity of the lumbar column tends to become
deformed by transformation into a posterior convexity. The result is
lasting tension of the long muscles of the dorsal region, and in the case
of women distension of the ligaments of the uterus. These two effects
explain the frequently occurring lumbar pains consequent on prolonged
sitting without a support for the back.
(4) A good chair for industrial work should be provided in addition
to a sufficiently wide seat with a support for the feet, having eventually
a movable oblique latticed step, a lumbar support, and where possible a
second support higher up. On account of the difference in height of the
back, the backs of these chairs should be either adjustable or they should
be provided in different sizes. A lumbar support which is upholstered
and not too narrow may satisfy both requirements.
(5) The height of the working bench and of the position of the object
to be manipulated should be adapted to the height of the worker when
seated, and this is most easily done by adjusting the position of the seat
and the support for the feet. The worker should be able to remain seated
in an upright position during work and should have a slight support for
his elbows. Every effort must be made to avoid as far as possible that the
method of work should involve unsupported movements of the forearms.
Work done in this way readily causes fatigue and is likely to lead to slight
trembling of the arms, which interferes with precision.
By judicious adjustment of the material and tools it is no
doubt possible to obtain solutions in the case of a great number
of processes which will satisfy the above requirements.
XXIV
Spittoons
The use of spittoons raises objections in certain countries
where it is considered a fundamental measure t o prohibit spitting
entirely. The absence of spittoons constitutes a tacit assumption
of this prohibition. Workers may elsewhere, when necessary,
use old boxes, etc., which are burned after use. Where, however,
the provision of spittoons is found to be necessary, they must
fulfil certain hygienic requirements. They should be fixed a t a
height of 1 metre above the ground and be supplied with a
(.: fl.Mi

C

34

STANDARD CODE OF INDUSTRIAL HYGIENE

device for rinsing them out with water, and must be so arranged
as to exclude desiccation and dissemination of their contents
in the air of the workrooms. The wall on which they are situated
should be painted white with a view to rendering visible any
soiling or contamination.

XXV
Privies
The ideal type is t h a t provided with an automatic water
supply. I t is highly desirable t h a t this type should be installed
in all establishments situated in localities provided with sanitation.
Where this is not possible, all technical means should be applied
with a view to preventing stagnation in channels leading to septic
trenches and liberation of odours or gas in the atmosphere of the
privy or its neighbourhood. The use of peat moss in trenches
has been advised on account of its disinfecting and deodorising
properties.
When the privies are not situated in the factory building and
do not communicate directly with it, sheltered passages should
give protection to their access, more especially in the case of
workers in establishments where they are exposed to heat and
likely to perspire. As far as possible, adequate heating should be
provided in privies, giving a temperature similar to t h a t in the
workrooms. At the same time, effective ventilation should be
maintained and an ante-room leading to the latrines should be
provided wherever the immediate proximity of workrooms renders
this necessary.
Partitions between the individual compartments of privies
should be constructed of wood, masonry or metal. They should
at all events be coated with washable paint or cement. The use
of wood is not advisable because of its lack of durability. Each
individual compartment should be provided with a door the height
of which should be at least 1-20 metres (4 ft.). The door should
be furnished with an inside lock.
The floor of privies should be constructed in material which is
easily cleaned and washed (concrete, asphalt, cement, tiles).
Wherever possible, privies should be situated near lavatories.
I n conclusion, inspection of privies is necessary in establishments where large numbers of workers are employed.

STANDARD CODE OF INDUSTRIAL

35

HYGIENE

2.—WORKROOMS SITUATED BELOW T H E L E V E L OF
T H E SURROUNDING GROUND
X X V I and X X V I I
Semi-Underground Premises
The workrooms referred to in the corresponding section
of the text of the Standard Code are those in which two-thirds
of the maximum height are below ground. They must in
consequence have windows opening outside. In certain cases
the formation of the adjacent ground permits of increasing the
access of air and light in these workrooms; this may be done
by constructing trenches 1-50 to 2 metres (59 to 79 in.) wide
and 1-50 metres (59 in.) deep, and by providing galleries as a
means of protection against the dampness of the surrounding
soil, for facilitating air circulation, and enlarging the angle of
incidence of the light.

5.—WORK U N D E R SHELTERS, PENTHOUSES, ETC.
X X V I I I and X X I X
The provisions given in the preceding sections in respect of
•working premises are also applicable to work under shelters,
penthouses, etc., in so far as it is possible to adapt them to
such conditions.

4.—UNHEALTHY OR OFFENSIVE TRADES
X X X and X X X I
•General and Special

Provisions

I t is of course understood t h a t in the case of processes
involving the adoption of hygienic measures of a special kind,
all the foregoing provisions must be applied a fortiori.
The
following constitute complementary measures the object of
which is to safeguard the health of the worker in industries
with a particular inherent risk.
c2

36

STANDARD CODE OF INDUSTRIAL HYGIENE

XXXII
Dampness, Steam, Vapour
Experience has proved that working capacity attains its
maximum when the surrounding atmosphere has a certain
temperature combined with a certain humidity rate; thermic
and hygrométrie values are interdependent and a variation in
one involves a corresponding variation of the other in inverse
proportion.
To express these variations, recourse is had to " air calories,"
which give the sum of the calories of the air and of the steam
contained in 1 cubic metre. It corresponds to the quantity
of heat required to raise the temperature of 1 cubic metre
(1-31 cub. yd.) of dry air from 0° to I o C. (32° P. to 33-8° F.),
and which equals about 0-3 calories. On the other hand, the
evaporation of 1 grm. of water requires 0-603 calories, that is
to say, 1 grm. of steam equals about 2 " air calories." Under
these conditions, according to research engaged in by Prött,
the optimum conditions in question would correspond to about
17-5° C. (63-5°F.) and 10 grm. of water per cubic metre of air,
which, expressed in " air calories," would correspond to about
37 • 5° C. (99 • 5° F.) temperature of the human body.
The figure of 37-5°C. expressed in "air calories" can be
arrived at by a whole series of combinations (Prött) : l
° C.
Grm.
Per cent.
13-9 and 12 of steam per cubic metre = 100 of " relative saturation "
17-8 „ 10
„
„
,,
83
19-8 „
9
„
„
„
75
25-7 „
6
50
31*6,,
3
„
25
,,
,,
tt
tf
37-5 „
0
„
„
„
0

The term " relative saturation " which, in the above table,.
replaces that usually employed, i.e. " relative humidity," means
the relation between the quantity of humidity contained in
1 cubic metre of air and that which corresponds to complete
saturation when the total caloric quantity of air humidity (and
not the temperature of the air) remains constant.
By comparing these figures with the humidity rates relative
to more or less corresponding temperatures, there may be found.
1

13-9° C . = 5 7 - 0 ° F .
37-5° C. = 99-5° F .
0-0648 grm. = 1 grain.

STANDARD CODE OF INDUSTRIAL HYGIENE

37

the following percentages and divergences between the wet and
dry bulb thermometers : 1
• C.
Grm.
Per cent.
14 and 12.1 of steam per cubic metre = 100 of relative humidity with
divergence of 0° C.
18
„ 10.2
„
,,
„
= 66 of relative humidity with
divergence of 3.5° C.
20
„ 8 . 9
„
„
„
= 50 of relative humidity with
divergence of 5.5° C.
25.5 „
6.3
,,
„
„
= 26 of relative humidity with
divergence of 10.5° C.

a
a
a
a

On the other hand, the temperature suitable for ordinary
work also oscillates between limits which practice has found
to be situated between 15° and 25° C. (59° and 77° F.).
From the preceding it will be seen that the relative humidity
rate calculated to avoid harm must He in the neighbourhood of
66 per cent., t h a t is to say, must vary so as to provide the value
which can be expressed in " air calories " approximating t h a t
which corresponds to the temperature of the human body.
I t is known t h a t a certain humidity rate of atmosphere is
often accompanied by the formation of mist and steam.
Measures requisite to prevent this consist in injecting a current
of hot air to supplement effective ventilation.
This method can only meet with success in well-constructed
workrooms, the roof of which is guaranteed against undue heat
loss and which does not favour condensation of steam clouds.
I t is essential that the temperature of the current of hot air
introduced should be maintained as near as possible to a figure
the value of which in calories added to t h a t of humidity calories
does not exceed the optimum of 37- 5° C. (99-5° F.), in accordance
with the indications above referred to.
X X X I I I , X X X I V and X X X V
Humidification
Humidification of workrooms may be effected in several
ways. The very bad method of humidifying the air by jets
of steam under pressure is merely mentioned with a view to
recommending its entire suppression. There may be distinguished in general three methods which permit of producing
the requisite evaporation necessary for supplementary humidification and ventilation to provide the required freshening of
»14° C. = 57-2° F .
25-5° C. = 77-9° F .
0-0648 g r m . = 1 grain.

3-5° C. = 6-3° F .
5-5° C. = 9 - 9 ° F .
10-5° C. = 18-9° F .

38

STANDARD CODE OF INDUSTBIAL HYGIENE

the atmosphere : these are saturation devices, atomisers and
spray apparatus. The first consist in apparatus by means of
which it is possible to humidify and freshen the atmosphere by
the application of air previously prepared in piping or apparatus,
such air only carrying the quantity of water corresponding to
its saturation point; atomisers or super-saturation devices
consist in apparatus in which preparation of damp air is made
in two stages : in the first, preliminary preparation takes place
analogous to t h a t effected in the saturation devices, the air
evaporating a quantity of water corresponding to its saturation
point ; in the second, completion of the preparation takes place
in the workroom, since the air carries with it, in the form of
mist, atoms of water ready for a second evaporation. Spray
apparatus consists in devices which operate in the workrooms
themselves, the preparation of the air not being effected in
special chambers or apparatus.
Control of the humidity rate is effected by means of diverse
methods, amongst which may be mentioned :
(1) Psychrometric method.—The Psychrometer consists of an
ordinary dry bulb thermometer and of another so-called " wet
bulb thermometer," since the bulb is surrounded by muslin which
dips into a receptacle containing water and which maintains it
in a damp state and causes constant evaporation at the surface.
The heat from vaporisation of the water is borrowed from the
reservoir of the thermometer, so t h a t the wet bulb thermometer
indicates, all other things being equal, a lower temperature than
the dry bulb thermometer. The difference is so much the greater
since evaporation is more rapid, as, for instance, when the air is
dry, t h a t is to say, further removed from its saturation point.
I t vanishes when the air is saturated.
For practical purposes, it is recognised that artificial humidification is not necessary from the point at which the wet bulb.
thermometer indicates at least 24° C. (75-2° F.). On the other
hand, it is true t h a t the humidity rate exceeds tolerable limits
when the wet bulb thermometer rises above 26° C. (78-8° F . ) ;
under these conditions work should be suspended.
Apart from that, it is essential t h a t there should be a
divergence not exceeding certain limits between the temperature
indicated by the dry bulb thermometer and t h a t indicated by
the wet bulb thermometer. In the cotton industry in England,

STANDARD CODE OF INDUSTRIAL

39

HYGIENE

for instance, this divergence is indicated by the following table,
expressed in Fahrenheit degrees :
Dry bulb
thermometer

Wet bulb
thermometer

Dry bulb
thermometer

Wet bulb
thermometer

50
51
52
53
54
55
56
57
58

48
49
50
51
52
53
54
55
56

59
60
61
62
63
64
65
66
67

57
58
59
60
61
62
63
64
65

Dry bulb
thermometer
68
69
70
71
72
' 73
74
75
76

Wet bulb
thermometer
66
67
68
68-5
69
70
70-5
71-5
72-5

(2) Katathermometric method.—The katathermometer is a
graduated alcohol thermometer from 100° F . (37-8° C.) to 95° F .
(35° C ) . This instrument is used for measuring what is called
the cooling rate, that is to say, the time which alcohol requires to
descend from 100° to 95° F . With this in view, the katathermometer is first of all heated by immersion in hot water to a
temperature well above 100° F., the instrument being provided
or not with a muslin cover according as to whether it is desired
to utilise it as a dry bulb or wet bulb thermometer. I t is
thereafter suspended in the air to be tested, and the time taken
in cooling is noted. The dry bulb instrument is cooled by
radiation and convection, whilst the wet bulb apparatus is cooled
by radiation, convection and evaporation, the latter depending
on the humidity rate of the air and the air movement.
In practice there exist formulae which permit of estimating
the humidity rate of the air and its rate of movement by means
of readings furnished by measurements effected simultaneously
when the dry bulb and wet bulb katathermometers are used. 1
The combination of the temperature, humidity rate and
movement rate of the atmosphere in certain proportions gives,
as the case may be, a more or less great sensation of comfort.
A similar sensation of this kind may, on the other hand, be
produced by different combinations, as is the case, for instance,
in the circumstances indicated below, which exert a refreshing
1
According to L. Hill, the cooling power needed to produce perspiration is
as follows for certain kinds of work :—
sedentary work
...
...
...
6 dry bulb k.-t.
light
„
9
„
„
„
hard
„
18
„
„
„

40

STANDARD CODE OF INDUSTRIAL HYGIENE

effect on the human body when clothed (Pittsburg) (experiments
effected by the United States Bureau of Mines).
Rate of air movement per minute
Relative
Humidity

0 m.

30 m.

100 m.

230 m.

Dry bulb thermometer temperature in ° C.

20
50
100

20-3°
19-2°
17-2°

21-4°
20-3°
18-6°

23-6°
22-5°
20-8°

25-3"
24-2°
22-8°

X X X V I , X X X V I I and X X X V I I I
Irritant Toxic or Asphyxiating Smoke, Fumes and Gases
Wherever circumstances permit, industrial operations involving utilisation, liberation, or production of smoke or/and
irritating asphyxiating fumes or gases should be effected in
hermetically closed apparatus. I n cases, and these are numerous,
where t h a t is impossible, devices should be applied with a view
to withdrawal of the dangerous products and should be arranged
as close as possible to the source of production or escape of the
products in question. Apparatus for apphcation of locahsed
ventilation are most commonly used and in general construction
these do not differ much from those applied for withdrawal of
dust (see below). I t is, of course, clear that as regards details
the various devices used require to be adapted to the special
object for which they are intended and that requisito modifications
in the model, construction, and site of the hoods, piping and
certain parts of the apparatus require to be effected in
consequence.
Removal of gas and fumes may be effected with a minimum
draught where the products to be eliminated are not present in
excessive quantities.
A good exhaust system for withdrawal of gas is usually
combined with ventilation of the workroom, since the elimination
of deleterious products and the stimulated circulation of air
brought about by the working of the apparatus in question
guarantees purification of the surrounding atmosphere. Every
effort must be made to avoid the production of harmful draughts.
In workrooms where heating apparatus is provided, the latter

STANDARD CODE OF INDUSTRIAL HYGIENE

41

inay be utilised for reheating air coming from the outside wherever
circumstances require this.
The efficiency of exhaust apparatus depends not only on good
construction b u t also on the manner in which it is maintained.
Duly qualified persons should be entrusted with inspecting the
state and regular working of apparatus of this kind.
According to' the kind of smoke or gas to be withdrawn, it
becomes necessary to utilise exhaust devices of the per ascensum
or per descensum type, the former being applied in the case of
light emanations while the latter is used rather for elimination of
heavy gases and fumes. I n the case of smoke, its dispersion in
the atmosphere is further prevented by causing it to pass through
chimneys known as " smoke-consumption chimneys." All
gaseous, irritant, toxic or harmful products collected in the
factory should be subjected to effective processes of condensation
(in water or other suitable liquids), chemical neutralisation,
saturation, or pyrogenous transformation (directed under the
hearth of the furnace or into a special furnace) or to equivalent
processes corresponding to the particular character of the gaseous
products in question. Where it is a question of complex gaseous
products, partly condensable and partly susceptible of pyrogenous
transformation, recourse is had to two or more of the abovementioned processes.
A modern improvement made in the technique for the purifying
of gas and smoke consists in the Cottrell method, the principle of
which is based on the flocculation of aerosols, brought about by
causing a variation in the electric charge protecting these particles.
I t is known t h a t mixing with an electrified aerosol another
dispersed substance charged with electricity of the opposite sign
produces an effect similar to t h a t present when the original
aerosol is formed of neutral particles ; the latter become charged
by induction by elements electrified by a sign contrary to t h a t
of their attraction. The Cottrell unit used in industrial technique
is formed essentially of a vertical metallic wire carried to very
high tension and enclosed in a vertical metallic tube of which
it forms the axis. The tube is earthed. The intensity of the
field thus created between the wire and the tube sets up intense
ionisation of the current of gas, steam, or dust-laden air passing
through the tube. The result is that all the solid particles in
suspension become discharged and form agglomerations which
finally collect in a collecting receptacle situated in the lower part
of the apparatus.

42

STANDARD CODE OF INDUSTRIAL HYGIENE

Premises likely to contain fumes or gases of an injurious or
inflammable nature should be abundantly ventilated before
workers are allowed to enter them ; when these premises contain
several apertures on opposite sides of the room, the latter should
be left open for several hours, prior to the commencement of
work, and when this is not feasible or where it is not possible
to provide a strong draught recourse must be had, prior to or
during the work, to injecting continuously a supply of air with
a view to renewing the atmosphere in the workroom.
X X X I X , X L and X L I
Dust1
The best protection against dust is furnished by the utilisation
of closed apparatus for all operations involving liberation of dust.
This method is, however, not always capable of realisation, and
in the numerous instances in which its application encounters
grave obstacles, it is necessary to provide suitable apparatus
ensuring exhaust draught, as near as possible to the source of
production of the dust in question.
In every system adopted there must be taken into consideration
the volume of the particles of dust and their specific weight with
a view to determining the amount of force necessary for their
withdrawal. Further, for technical reasons it is important to
ascertain whether there is continuous production of the dust in
question or not, and also to recognise its possible value with a
view to eventual recuperation.
The collection of dust at its point of origin is not always easy.
The apparatus and processes applied for this purpose are so varied
t h a t it is not possible to adjust the dust collector a t any special
point except by provision of a special technical device. For
ordinary dusty processes exhaust hoods in wood or metal are
constructed or at times a sleeve-shaped cloth collector is used;
the dust is removed as near as possible to its point of origin
and withdrawal is effected by means of exhaust through a system
of piping by means of mechanically operated ventilators.
At the present time there are on the market numerous constructions neither too costly nor too cumbersome and which
satisfy the essential conditions required from plant of this kind,
t h a t is to say, are capable of adjustment close to the dust1
The observations apply to cases where humidification to precipitate the
duet is impossible for technical or financial reasons.

STANDARD CODE OF INDUSTRIAL HYGIENE

43

producing apparatus and of being brought into close contact
with all points at which dust may be produced.
In other cases, the mouth of the exhaust apparatus is situated
below the working post eUminating the dust per descenswm :
whether it is a case of sieves or perforated tables, there always
comes into play the same principle, by virtue of which the
materials under manipulation yield their dust to the aperture
which absorbs them, thus preventing their dispersion in. the air.
At times the action of this exhaust device—hood or other
apparatus—is reinforced by a draught blowing in the direction
of the withdrawal, that is to say, in the direction from the worker
towards the ventilating apparatus.
The large pipe intended to direct the dust towards a special
collector or outside the factory should possess a diameter increasing
with the flow of the current, in order to avoid interference with
the free circulation of the dust-laden air. Similarly, its length
should not be excessive, thus constituting a source of resistance
to evacuation. Further, elbow bends and angles should be
accurately calculated so as to facilitate the dust withdrawal.
The interior surface of the piping should be smooth and in no
wise adhesive. Traps for deposit of heavy dusts and small
apertures permitting of cleansing should be arranged here and
there throughout the length of the piping.
Branch pipes should never form a right angle with the principal
piping and two branch pipes should never be placed opposite one
another. Similarly, it is essential to avoid pipes having a Y
formation, since two conflicting draughts retard circulation and
may at times choke the apparatus. The cross-section of the
central piping must at one point be equal to the sum of the
cross-sections of the branch piping which has entered it up to
that point.
When a series of exhaust pipes are connected up with the
same ventilator, it is essential t h a t the intensity and rapidity
of the air withdrawal should be equal in all the pipes in question.
Where this is not so, there is a risk of the circulation becoming
arrested in those pipes in which it is less rapid.
The type of ventilator used for aspiration of dust varies in
accordance with the nature of the industrial operations. The
propulsion type is only applied in relatively small workrooms
possessing piping with a large diameter and not requiring withdrawal of large quantities of dust. In all other cases it is
preferable to use centrifugal ventilators, the working capacity

44.

STANDARD CODE OF INDUSTRIAL HYGIENE

of which (size, number of revolutions) should be suitably adapted
to the work in course of execution.
I t is sometimes necessary to have a mobile exhaust apparatus,
notably for cleaning dusty workrooms. I n this way the use of
dusters or blowers is avoided.
Wherever a powerful dust exhaust apparatus is used, measures
must be taken with a view to ensuring renewal of the air removed
by ventilator. Without this precaution the working of the
exhaust apparatus would be rendered difficult, especially when
the doors and windows of the workroom are kept closed. I t
is further necessary to entrust competent persons with the
inspection and supervision of dust-exhaust apparatus. Dust
withdrawn from the workrooms is directed into collectors, dust
chambers, cyclone separators, water separators, either floating
or with injection of water or felt filters. As in the case of gas,
fumes and smoke, precipitation by the electrostatic method is
also used for dealing with dust. This method even permits of
fractionated precipitations of dusts, formed of several dispersed
constituents possessing varying volatility. With a view to this,
Cottrell unities are grouped, or use is made of vertical wires
a t high tension arranged in parallel layers and separated by
metallic sheets similarly vertical and parallel, and earthed, the
wires being enclosed in chambers of masonry. Electric precipitation thus enables recovery of dusts which are of special marketable
value.
Individual protection.—A supplementary measure of equal
importance in workshops where smoke, gas, fumes and dust
are freely given off consists in the provision of working
clothes. I n all such places employers should be obliged to
place at the disposal of their workers working clothes or overalls,
whilst cloakrooms enabling the workers to change their clothes
and hang up their town clothes should likewise be provided.
Working clothes are generally made of a smooth and close
material, often impregnated with a substance preventing the
adhesion of dust or other products handled during work. They
should cover the body entirely and prevent irritating substances
from penetrating at the neck and wrists. Head gear should be
provided for protecting the head, and where irritating products
are handled the workers require to be furnished with gloves, and
a t times also with masks. Various types of these are in use,
chief amongst which are respirators, anti-gas masks, respiratory

STANDARD CODE OP INDUSTRIAL HYGIENE

45

apparatus with provision of oxygen, masks with flexible piping
connected with an exterior source of fresh air, and finally liquid
oxygen apparatus. Respiratory apparatus must be of strong and
simple construction and easy manipulation and made of lasting
material. They should be of simple and sure usage, even when
in the hands of inexperienced workers hable to the effects of
emotion. They must be perfectly airtight a t all points and no
part thereof should be subject to constant negative pressure
which is likely to favour entry of dust should they not remain
absolutely airtight. They should be easy to wear and should
not give rise to any interference with movement nor any
irritation of the skin at the points of contact or of application.
The respiratory apparatus however ought to be closely applied
to the face, and with a view to this it is essential t h a t each worker
possesses an apparatus which fits him. W h a t is known as the
" deadspace " should be as small as possible. They should, as
far as possible, leave the chest and arms free and should not
present a striking or ridiculous appearance. Further, they
should permit of the execution of normal work without causing
respiratory inconvenience or discomfort, and should be provided
with a device permitting of elimination of the necessary portion
of C 0 2 from the expired air.
Finally, they should lend themselves readily to inspection and
disinfection, and where they are provided with a mouthpiece they
should possess a saliva trap and a nose clip.
Mention should also be made here of goggles for protecting
the eyes against dust, gas, fumes, etc.
Where necessary, lavatories or douche baths should be placed
at the disposal of workers on leaving work.
As regards douche baths, these should be arranged in separate
compartments with a view to avoiding promiscuous use. These
compartments should have dimensions not inferior to 1-50 metres
(5 ft.) in width by 1-50 to 3 metres (5 to 10 ft.) in length,
according as to whether it is a question simply of douches or
of baths. The latter are usually preferred by women workers,
while men ordinarily use the douches. I n providing douche
baths for women it is preferable to install those with a ring
spray rather than a head spray to avoid wetting the hair. I n
the bathing cabins a free space should be provided between the
ground and the bath in order to allow the water to run off.

46

STANDARD CODE OF INDUSTRIAL HYGIENE

Construction material should be so chosen as to permit of
rapid cleansing. All requisite toilet accessories (soap, towels,
lockers) should be provided.
X L I I , X L I I I and X L I V
Large Furnaces
Heat-radiating furnaces should be installed in a room or
«ompartment specially destined for this purpose wherever lack
of space renders impossible protection of those workers not
directly occupied at the furnaces.
The Avorkers who attend the furnaces should be specially
protected against the harmful action of heat radiation. I n
certain instances it is advisable to circulate a current of fresh
air drawn from outside (previously slightly heated in winter)
between the glowing furnaces and the worker tending it.
Precautions must in such a case be taken to avoid workers
•catching chills likely to lead to neuralgic or rheumatic affections.
A system of rotation of shifts is generally in force with a
view to reducing to a relatively short period the time spent in
front of the furnace. With this in view, the number of workers
should exceed (usually a t least twice) the working posts,
permitting one shift to recover whilst the other is in action.
Special rest rooms must in such a case be placed at the disposal
of the workers.
Certain furnaces are provided with doors, sometimes double,
with an intervening space in which cold water may be circulated. 1
In this manner the worker is protected against heat stroke.
The openings arranged in the doors for the introduction of tools
a n d supervision of the process are mostly provided with sliding
plates, the closing or opening of which enables the emergence
of heat radiation to be checked as required. Finally, cast-iron
screens, sackcloth or fireproof screens (asbestos) are currently
employed for protecting workers particularly exposed. Where
necessary, fireproof clothing or certain fireproof garments should
be worn by these workers.
The eyes should be protected against the action of heat
radiation by means of protective glasses. The conditions which
such glasses should fulfil may be summarised as follows : they
should be as light as possible, easy and comfortable to wear, and
1

air.

The worker can also be isolated by means of " curtains " of water or fresh

STANDARD CODE OF INDUSTRIAL HYGIENE

47

should not give rise to friction or irritation. They should have
solid and durable frames constructed of material capable of
resisting possible harmful influences connected with working
conditions. Further, the glasses should in no wise interfere with
vision and should be replaceable. The visual field should be as
large as possible and the glasses should be so mounted as to
permit of the free access of air, to prevent heating of the eyes
and the formation of steam. The form and colour of the glasses
should constitute an effective means of protection against the
harmful agent. Periodical control of the filtering power of
glasses should be instituted. Finally, such glasses should not
prevent the worker requiring these from wearing at the same
time ordinary glasses for correcting visual defects.
In certain cases fireproof helmets covering the whole head and
provided with transparent glasses are provided.
In further instances, as for example in glass works, special
apparatus exists allowing of automatic dropping of a protecting
screen between the source of radiation and the worker whenever
the latter is obliged to proceed to the opening of an incandescent
furnace.
Finally, it is advisable to provide special shoes for workers
tending furnaces with a view to preventing burns, to which they
are exposed.
XLV
Drying-Rooms, Stoves
Apart from the precautions to be taken enumerated in the
text of section XLV of the Code, attention must be paid to the
quality of the atmosphere in constructions serving as stoves and
drying-rooms at the moment when workers are obliged to enter
these. The accumulation of gas or other volatile products given
off by the substances to be dried or by combustion become so much
the more dangerous in such cases, since ventilation apertures are
often closed down in constructions of this kind with a view to
raising the temperature.
XLVI
Noise, Vibration, Shocks
Protection of workers against noise involves the adoption of
several measures, certain of which are applicable to the worker
and certain others to the work.
Amongst the former may be enumerated the use of cotton
wool ear-plugs or other obturating devices, or of protective

48

STANDARD CODE OF INDUSTRIAL HYGIENE

helmets. The latter, it must be confessed, are generally
uncomfortable and the workers are disinclined to use them.
Medical examination on commencing work is advisable with a
view to eliminating workers predisposed to ear trouble or
suffering from diseases of the ear. Similarly, medical inspection
(periodical examination) should be effected with a view to
detection and timely treatment of derangements of hearing.
A final measure consists in organising alternating shifts of workers
in order to provide the most frequent interruptions possible of
the work.
Measures applicable to the work itself are more rational
since they aim at suppressing the cause of noise and not its
effect, as in the case mentioned above. It is here a question
of technical measures tending to insulate and deafen noise. In
their entirety, these measures may be classed with those generally
adopted for protection against shocks and vibration. They
cannot be determined except after detailed examination of the
surrounding conditions and they vary in accordance with these.
Generally speaking, covering of walls, ceiling and especially of
floors with material intended for deadening noise reduces the
production of vibrations by way of the floor (felt, rubber, linoleum,
" acoustic," " celtothex," " akoustolith," various special plasters,
etc.). Vibration from machinery may be deadened by special
arrangement of the machines on supports made of special
substances or by placing them on special bases which are
constructed independently from the flooring used by the workers.
They may further be isolated in special closed chambers having
thick iron doors.
XLVII
Poisons1
Since measures of protection against the various poisons do
not differ essentially from those against gas, fumes, smoke and
dust, the reader is referred to the parts of the Explanatory Notice
where these causes of injury are dealt with.
»

1
For further information under this head, see Occupation and Health,
Encyclopœdia of Industrial Hygiene, 2 vols. Geneva, International Labour
Office, 1930-1934.