VENTILATION

Ventilation is the dynamic parameter that complements the concept of air space. For a given

number of workers, the smaller the work premises the more should be the ventilation.

Ventilation differs from air circulation. Ventilation replaces contaminated air by fresh air,

whereas as the air-circulation merely moves the air without renewing it. Where the air temperature

and humidity are high, merely to circulate the air is not only ineffective but also increases heat

absorption. Ventilation disperses the heat generated by machines and people at work. AdequateExcept for confined spaces, all working premises have some minimum ventilation. However,

to ensure the necessary air flow (which should not be lower than 50 cubic metres of air per hour

per worker), air usually needs to be changed between four to eight times per hour in offices or

for sedentary workers, between eight and 12 times per hour in workshops and as much as 15

to 30 or more times per hour for public premises and where there are high levels of atmospheric

pollution or humidity. The air speed used for workplace ventilation should be adapted to the air

temperature and the energy expenditure: for sedentary work it should exceed 0.2 metre per

second, but for a hot environment the optimum speed is between 0.5 and 1 metre per second.

For hazardous work it may be even higher. Certain types of hot work can be made tolerable by

directing a stream of cold air at the workers.

Natural ventilation, obtained by opening windows or wall or roof airvents, may produce

significant air flows but can normally be used only in relatively mild climates. The effectiveness

of this type of ventilation depends largely on external conditions. Where natural ventilation is

inadequate, artificial ventilation should be used. A choice may be made between a blown-air

system, an exhaust air system or a combination of both (‘push-pull’ ventilation). Only ‘push-pull’

ventilation systems allow for better regulation of air movement.

V. WORK-RELATED WELFARE FACILITIES

Work-related welfare facilities offered at or through the workplace can be important factors.

Some facilities are very basic, but often ignored, such as drinking-water and toilets. Others may

seem less necessary, but usually have an importance to workers far greater than their cost to

the enterprise.

1. DRINKING WATER

Safe, cool drinking water is essential for all types of work, especially in a hot environment.

Without it fatigue increases rapidly and productivity falls. Adequate drinking water should be

provided and maintained at convenient points, and clearly marked as “Safe drinking water”.

Where possible it should be kept in suitable vessels, renewed at least daily, and all practical steps

taken to preserve the water and the vessels from contamination.

2. SANITARY FACILITIES

Hygienic sanitary facilities should exist in all workplaces. They are particularly important where

chemicals or other dangerous substances are used. Sufficient toilet facilities, with separate

facilities for men and women workers, should be installed and conveniently located. Changingrooms and cloakrooms should be provided. Washing facilities, such as washbasins with soap and

towels, or showers, should be placed either within changing-rooms or close by.

3. FIRST-AID AND MEDICAL FACILITIES

Facilities for rendering first-aid and medical care at the workplace in case of accidents or

unforeseen sickness are directly related to the health and safety of the workers. First-aid boxes

should be clearly marked and conveniently located. They should contain only first-aid requisites

of a prescribed standard and should be in the charge of qualified person. Apart from first-aid

boxes, it is also desirable to have a stretcher and suitable means to transport injured persons to

a centre where medical care can be pr

ventilation should be looked upon as an important factor in maintaining the worker’s health and

productivity.

4. REST FACILITIES

Rest facilities can include seat, rest-rooms, waiting rooms and shelters. They help workers to

recover from fatigue and to get away from a noisy, polluted or isolated workstation. A sufficient

number of suitable chairs or benches with backrests should be provided and maintained, including

seats for occasional rest of workers who are obliged to work standing up. Rest-rooms enable

workers to recover during meal and rest breaks.

5. FEEDING FACILITIES

It is now well recognized that the health and work capacity of workers to have light refreshments

are needed. A full meal at the workplace in necessary when the workers live some distance away

and when the hours of work are so organized that the meal breaks are short. A snack bar, buffet

or mobile trolleys can provide tea, coffee and soft drinks, as well as light refreshments. Canteens

or a restaurant can allow workers to purchase a cheap, well-cooked and nutritious meal for a

reasonable price and eat in a clean, comfortable place, away from the workstatio