This standard specifies the occupational exposure limits of chemical hazards on workplace.
This standard is applicable to the design of industrial hygiene and various workplaces exist or generate chemical hazards. Is applicable to monitor, assess and control of the hygiene condition on, labor condition, exposure degree of chemical factor for worker, leakage of production plant and the effect of protective measures on workplace, and the supervision on occupational health.
This standard is not applicable unprofessional contact.
2 Normative References
The following documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent modification does not apply. However, all parties coming to an agreement according to this standard are encouraged to make use of the latest edition of these documents. For undated references, the latest edition of the normative document is applicable to this standard.
GBZ 1 Hygienic Standards for the Design of Industrial Enterprises
GBZ 159 Specifications of Air Sampling for Hazardous Substances Monitoring in the Workplace
GBZ 160 Determinations of Toxic Substances in the Air of Workplace
3 Terms, Definitions and Abbreviations
The following terms, definitions and abbreviations are adopted in this standard:
3.1 Occupational exposure limits, OELs
It is refers to the exposure limit values of occupational hazardous agents The allowable exposure level that will not cause harmful health effects on the majority of contacts during the long-term repeated exposure in the occupational activities. The occupational exposure limits of chemical hazards include permissible concentration-time weighted average, permissible concentration-short term exposure limit and maximum allowable concentration.
3.1.1 Permissible concentration-time weighted average, PC-TWA
It refers to the average allowable exposure concentration of 8h working day and 40h week taking time as weight number.
3.1.2 Permissible concentration-short term exposure limit, PC-STEL
It refers to the allowable exposure concentration in short time (15min) under the premise of complying with PC-TWA.
3.1.3 Maximum allowable concentration, MAC
It refers the concentration of toxic chemicals that cannot be exceeded at workplace at any time within a working day.
3.2 Excursion limits
It refers to the multiple value of PC-TWA that the exposure concentration of chemical hazards without PC-STEL at any short time (15min) shall not exceed at the condition of meeting 8h permissible concentration-time weighted average.
3.3 Workplace
It refers to all places that worker engaging in occupational activities.
3.4 Work site
It refers to the places that the workers frequently or regularly stay at for engaging in the occupational activities or production management.
3.5 Chemical hazards
The chemical hazards in this standard include not only substances and dust but also biotic factors.
3.6 Total dust
The dust can enter the entire respiratory tract (nose, pharynx and throat, chest bronchi, bronchioles and alveoli) hereinafter referred to as total dust. It refers to all the dust measured at breathing zone by total dust collector according to standard method in technical.
3.7 Aerodynamic diameter, dae
If the sedimentation rates of a particulate (any shape and density) and spherical body with relative density 1 in the static or laminar flow air are equal, the diameter of the spherical body is regarded as the aerodynamic diameter of this particulate.
3.8 Respirable dust
For the dust particle (can enter alveoli) collected according to the standard test method of respirable dust, any aerodynamic diameter is under 7.07μm; the sampling efficiency of dust particle with aerodynamic diameter 5μm is 50%, which hereinafter referred to as "respirable dust".
