WORKING ENVIRONMENTMEASUREMENT SYSTEM IN JAPANJapan Association of Working Environment Measurement
Tokyo, JAPAN2010.05.20

Occupational Health Control
1 . Introduction○Workplaces→many kinds of hazardous factors
building,facilities,equipments,machinery,materials,chemicals
mental stress due to work organization,etc.,・・・・・
・・・・・
if not adequately controlled→may cause adverse effect on workers’ health→may cause industrial injury or even death○Hazard and Risk
Hazard：：hazardous nature and its degree
the object(chemicals,machinery etc.,) inherently possess
Risk：：the severity and the extent of possibility of occurrence of injuries or
diseases that might be caused due to the hazards

Occupational Health Control
2 . Five pillars of occupational health control○ working environment control○ work control○ health control＜3-way approaches of occupational health control＞○ the structure/organization in the workplaces
to implement occupational health control○ workers education on occupational safety andhealthWorking Environment Control- the basis of good control ○What is “Working environment control”?
→ to eliminate or control hazardous factors from working environment
by technical/engineering methods such as local exhaust ventilation,etc..
to the level that may not cause any unacceptable risk to workers→this approach is the basis of occupational health control○ The first step of working environment control→ “working environment measurements”.
○ Result of the measurements→measures to improve /repair /replace equipment /machineryor change in the operation etc., if necessary○ This process is incorporated in “the Industrial Safety and Health Law of1972””, that is the central and comprehensive law of this sphere.

Characteristics of Japanese Working
environment measurement○ measurement of the airborne concentration of chemicals/mineral dusts/asbestos
fibers, etc ., in the workplace atmosphere→statistical treatment of the measurements results to calculate geometrical meanvalue and geometrical standard deviation→to calculate indices to be compared with “control levels” that are values
stipulated for each hazardous chemicals by the government→comparison between “indices” and “control levels”→determination of “which Class Ⅰ,Ⅱ
ⅡorⅢ
Ⅲ the workplace falls”
・if Class Ⅰ→the workplace condition is good and no action isneeded・if Class Ⅲ→the workplace condition needs improvement torealize Class Ⅰ
・If Class Ⅱ→ the workplace condition is between ClassⅠ
Ⅰand Ⅱ
it is encouraged to realize Class Ⅰby checking theworkplace condition and taking necessary actionComparison of Japanese methodwith those of US/European method○ Japanese methods→measuring airborne concentration without regards ,principally,to workers
exposure concentration→the result is used for evaluation of workplace conditions as to whether any
action for improvement is needed or not .
＊main purpose→to lead to working environment improvement○ US and most European countries’ method→measuring workers’ exposure to chemicals→in terms of 8 hours‘‘ time weighted average→ compare results with “Occupational Exposure Limits（（OEL)
for respective chemicals OELs are recommended fromsome of the institutions such as TLVs from ACGIH.
＊main purpose→to evaluate workers’ exposure

The merit of Japanese system① better practicality/feasibility for employers to makemeasurement→measuring airborne concentration is easierthan measuring exposure of each worker② closer connections between results ofmeasurement and the identification of the
facility/equipment that needs improvement

2 History of Working Environment
Measurement○ Although the Labor Standards Law of 1947 did not enforce employers aworking environment measurement, a research was initiated in 1954
under the government support for industrial health experiments andresearch to develop measuring methods in order to encourage suchmeasurement．
．
○ The findings of this research were published as the “Guidelines for
Working Environment Measurement””in 1958.
○ In these guidelines, new measuring methods were prepared andappropriate ones were selected from among the conventional methods,
necessary improvements were made to them after a series ofexperiments,and research was also done on those substances for whicha measuring method was not established．
．
○ The revised edition with newly added methods were published in
1964．
．

○ In 1960，the Ordinance on Prevention of Organic Solvent
Poisoning was enacted under the Labor Standards Law．
○ Under this ordinance，the concentration of organic solventsin the atmosphere was to be measured once every threemonths in indoor workplaces where the organic solvents
designated by the Minister of Labor are put to constant use．
○In 1967，the Ordinance on Prevention of Lead Poisoning wasenacted．This ordinance made it mandatory to measure theconcentration of lead in the atmosphere in indoor workplaces
where lead is handled and lead vapor，fume and dust are
constantly generated.

○The Ordinance on Prevention of Hazards due to Specified

Chemical Substances was enacted in 1971．
．It is stipulated inthis Ordinance that at indoor workplaces where Group 1 and
2 substances are produced or handled constantly，，theconcentration of gas，
，fume or dust in the air shall bemeasured．
．
○With regard to the specified chemical substances，，aCommittee for the Research of Measurement Methods ofHazardous Substances in the Working Environment wasorganized with experts participating．
．For the chemical
substances controlled under this ordinance，，attempts weremade to establish a system for the measurement of theirconcentration in the atmosphere of the working
environment，，and the findings were published under thetitle “Guidelines for the Measurement of the Working
Environment”in 1972．
．

○ In accordance with the change of working conditions and status ofoccupational diseases, the Ministry of Labor has enacted and revised
legislation pertinent to industrial safety and health，，○ As new techniques and substances were developed one after another,and there were no clear indication of decreasing trend of industrial
accidents ,government realized that ,instead of Labor Standard Law, a
new comprehensive Law that focused only on the industrial safety andhealth issue was necessary.
○ Given this situation，，the Industrial Safety and Health Law, the firstcomprehensive one in this sphere, was enacted in 1972．
．
○ The item “Working Environment Measurement’ was newly
incorporated as Article 65 .
○ Nevertheless，，this article provided merely for the obligation to carry out
necessary measurement at indoor workplaces，，etc.，， where hazardous
work would be conducted and to keep its records，，but the ministry had
not come up with any of the detail on the measurement methods.
○ Thus the article, at the initial stage, substantially had no binding poweron the measurement methods .

• In order to assure accurate working environment
measurement，the “Working Environment
Measurement Expert” was introduced in the newlaw entitled “Working Environment measurement
Law” that was enacted in 1975．
• On the other hand, Article 65 of the Industrial Safety
and Health Law was amended and stipulated thatthe measurement shall be carried out in accordancewith the Standards for Working Environment
Measurement stipulated by the Labor Minister．

3 . The Overview of Article 65of the Industrial Safety and Health Law○The employer shall ensure the measurement of temperature，，humidity，，concentration of dust，，chemicals etc.，，and shall keep records in regard tospecified workplaces，，such as those where risky work will be performed．
．
○The working environment measurement shall be carried out inaccordance with the working environment mesurement standards
prepared by the Minister of Labor．
．
＜Justification of the measurement and evaluation method＞＞○ The airborne concentration of toxic substances in the workplaces
generally varies to a significant degree even if the measuring point andtime are fixed.
○ Given this factor，，in order to make an accurate quantitative assessmentof the working environment，，there is a need to statistically process datawith consideration given not only to the mean concentration but to thedegree of variance as well，，
And the measuring method was developed in line with the above
concept.

Definition of Working environment
measurement by law○ The “working environment measurement” by thelaw consists of （1）design，（2）sampling and （3）analysis，○“Design” is particularly important so that the result of
the statistical treatment of figures obtained from eachsampling point rightly reflect the actual state of
airborne concentration of chemicals.
○ The method of “Design” is stipulated by Minister’s
Notice entitled “working Environment Measurement
Standards”

Design and sampling○According to the notice, the “design” and “sampling” should follow the
below ;
(1) Vertical and horizontal lines are drawn at equal intervals of not morethan 6 m on the floor of a unit work area (refers to such a necessary
section that is designated for working environment based on thecondition of distribution of harmful substances and range of movementof workers within the area of a workshop concerned, hereinafter thesame shall apply) and a sampling point is provided at each intersectionof those lines at a position 50 to 150 cm above the floor (except such a
point where measurement is very difficult due to equipment etc.).
However, when it is obvious that the concentration of chemicals/dusts issubstantially uniform, vertical and horizontal lines can be drawn at equalintervals of more than 6 m on the floor of a unit work area and asampling point provided at each intersection of those lines.

Design and sampling(conti-)(2) Sampling points shall be provided at not less than 5 points
though when they become less than 5 points then the above
rule is applied regardless of the provisions of the preceding
item. However, when the unit work area is very narrow and it
is obvious that the concentration of chemicals/dust is
substantially uniform, the number of sampling points may beless than 5.
(3) The measurement prescribed in the preceding section shallbe made at suchtime when work is regularly performed.

A-measurement and B-measurement(1) Measurement of airborne concentration is considered to be practical andsimple in order to obtain the information on where the problems
exist ,whether improvement of the instruments/equipments areneeded.
The measuring method in this purpose is called “A-measurement”.
(2) The workers’ temporary high exposure ,however, due to the emission
conditions of toxic substances and working postures etc., are perhaps
overlooked only by the above measurement（（A-Measumement））
practiced at the unit work area．
．
Therefore，，the concentration at a certain place and time at which
workers’ exposure is considered to become maximum level must be
measured separately. This type of measurement is called Bmeasurement and complementary to A-measurement.
(3) It is usual that Both A-measurement and B-measurement are
performed at a unit work area．
．

administrative control level○ The concentration for administrative regulation of airborne
toxic substances is termed “an administrative control level“and distinguished from the “occupational exposure limit．
．”○The administrative control level is an index to determine thecontrol class to judge the propriety of the working
environment control，based on the results for working
environment measurement which have been implemented forthe unit work area in accordance with the Working
Environment Measurement Standards．
○ The administrative control level have been established froman administrative point of view to achieve the purpose of theworking environment control，based on the technologicalfeasibility and international trends concerning working
environment control，as well as the trend in standards for
exposure control adopted in many countries and exposure
limits proposed by academic societies．

Conti○ More concretely，measured values should becompared with the administrative control
level after statistical treatment．The
administrative control level should not becompared with individual measured values．
○Thus，the administrative control level isdifferent from the occupational exposure
limits(OEL)4．Overview of Article 65-2 of Industrial Safety and Health
Law○In 1988 the Industrial Safety and Health Law wasamended to be added a new Article 65-2 about
evaluation of working environment measurement
and so on．
○In this amendment it was stipulated that ①theevaluation of working environment measurement
result shall be carried out in accordance with theStandards for Working Environment Evaluation
prepared by the Labor Minister and ②when it isdeemed necessary to work for the protection of theworkers’health，appropriate measures shall be taken
for facilities including their installation,repair,etc.,

Points of Article 65-2 of Industrial Safety and HealthLaw○the employer shall，where on the basis of the result of
evaluation of the working environment measurement under
the provision of Article 65 he deems it necessary for
maintaining the health of workers，establish or improve thefacilities or arrangement．
○ The evaluation of the result shall be carried out in accordancewith the “Standards for Working Environment Evaluation”
stipulated by the Labor Minister．
○ The employer shall keep the records of the result．

Control Class Ⅰ＜condition of working area＞
Concentration of airborne hazardous chemical
does not exceed the administrative control
level at almost (more than 95%)points.
＜measures to be taken＞
Nothing to be taken. To continue the current
working environment control to keep thepresent condition

Control Class Ⅱ＜condition of working area＞
Mean concentration of airborne hazardous
chemical does not exceed the administrative
control level .
＜measures to be taken＞
Try to take necessary measures ,based on the
result of inspection offacilities,equipment,operation or work
procedureControl Class Ⅲ＜condition of working area＞
Mean concentration of airborne hazardous chemical
exceedｓ the administrative control level .
＜measures to be taken＞①Take necessary measures, as soon as possible, basedon the result of inspection of facilities,
equipment,operation or work procedure②Use effective respirator, if necessary.
③carry out medical examination or other measures, if
necessary.

Classification of control class(1)“A-sampling only” case
Ea<E

Ea1≧E≧Ea2 Ea2＞EClass ⅠClass ⅡＣｌａｓｓ ⅢClassification of control class(2)Both “A-sampling “and “B-sampling” case
Ea1＜E

Ea1≧E≧Ea2

Ea2＞E

CB＜E

Class Ⅰ Class Ⅱ

Class Ⅲ

E1≧CB≧1．
5×E

Class Ⅱ Class Ⅱ

Class ⅢCB＞1．5×E

Class Ⅲ Class Ⅲ

Class Ⅲdefinition
1st．Evaluation Value（Ea1）
Estimated value suited to 5％ from the highest level
among the actual value of airborne toxic substances
at working hours at all possible points in a unit work
area．
2nd．Evaluation Value（Ea2）
Estimated value of the arithmetic mean concentrationof airborne toxic substances in a unit work area．
-fin-(by S.Asuka)