31. Ventilation, temperature and humidity.–Every employer of a building or other construction work shall ensure that:-

(i) where an employee is likely to be exposed to any chemical, physical or biological hazard to such an extent as is liable to be dangerous to health, appropriate preventive measures are taken against such exposure;

(ii) the preventive measures referred under sub-rule (i) above shall comprise of-

(a) the replacement of hazardous substances by harmless or less hazardous substances wherever possible; or

(b) technical measures applied to the plant, machinery, equipment or process:

Provide that where it is not possible to comply with sub-rule (ii), other effective measures, including the use of appropriate personal protective equipment and protective clothing are provided free of charge.

(iii) where employees are required to enter any area in which a toxic or harmful substance may be present or in which there may be an oxygen deficiency or a flammable atmosphere, adequate measures are taken to guard against danger;

(iv) whenever heat stress, cold or wet conditions are such that they can lead to impairment of health or extreme discomfort, preventive measures are taken, such as-

(a) proper design of the workload and workstation, with special regard to employees in cabins, and command or driving operations;

(b) training, to enable detection of early signs of disorders;

(c) supply of appropriate protective equipment and clothing;

(d) routine medical surveillance;

(e) drinking water and electrolyte.

(v) necessary steps are taken to constantly provide at all work places of the building or other construction work site, adequate ventilation to clear away smoke and fume, steam and dust, to dilute gases that are inflammable or noxious so as to render them harmless, to provide air containing sufficient oxygen and to prevent such excessive rise of temperature or humidity which may be harmful to the health of the persons employed therein;

(vi) where the nature of the work carried out in the building or other construction work site involves or is likely to involve production of excessively high temperatures, adequate measures as are practicable are taken to protect the employees therefrom, by separating the process which produces such temperatures from the workplace, by insulating the hot parts or by other effective means;

(vii) where part of the risk arises from the metabolic heat produced during work or from direct exposure to sunlight and high outdoor air temperatures, and when other methods of eliminating the risk are impracticable, a work-rest cycle for exposed employees, preferably in a shaded, cooler resting space shall be provided to allow the employee to recover;

(viii) measurement of air quantity, temperature and humidity are regularly taken and brought up to date the entries at each air measurement station;

(ix) ventilation in tunneling shall provide for -

(a) removal of the pollutants (exhaust gases of the vehicles, blasting fume, dust) and establishment and maintenance of a climatic state (temperature, humidity) in accordance with the required physical activities of the work force in the underground building or other construction work sites;

(b) choice of the ventilation system for a specific site depending on the complexity of the project (tunnel length and diameter, single or double bore, cooling requirements, intermediate multifunction stations, etc.);

(c) natural or artificial ventilation be so designed as to introduce a sufficient quantity of fresh or purified air per person and per hour into an area, considering the nature and conditions of the work;

(d) appropriate measures are taken to ensure that in enclosed premises a suitable hygrometric level in the air is maintained;

(e) the following instruments on the tunneling site-

(i) Oxygen level measuring instrument;

(ii) presence of flammable gases measuring instrument;

(iii) temperature measuring instrument;

(iv) dust concentration measuring instruments; and

(v) toxic gas measuring instrument.

(f) the air supply intake points for all air compressors located at places where such intake air does not get contaminated with dust, fumes, vapor and exhaust gases or other contaminants.