Table. Occupational Exposure Limits

 

	8hr TWA	15 min STEL
Substances Assigned a Maximum Exposure Limit
Beryllium	0.002 mg/m 3
Cadmium oxide fume (as Cd)	0.025 mg/m 3
Chromium VI compounds (as Cr)	0.05 mg/m 3
Cobalt	0.1 mg/m 3
Nickel (insoluble compounds)	0.5 mg/m 3
Substances Assigned an Occupational Exposure Standard
Welding fume	5 mg/m 3
Fluoride (as F)	2.5 mg/m 3
Iron oxide, fume (as Fe)	5 mg/m 3	10 mg/m 3
Zinc oxide, fume	5 mg/m 3	10 mg/m 3
Manganese, fume (as Mn)	0.5 mg/m 3
Ozone		0.2 ppm
Nitric Oxide	1 ppm
Nitrogen dioxide                                             1 ppm
Chromium III compounds (as Cr)	0.5 mg/m 3
Barium compounds, soluble (as Ba)	0.5 mg/m 3
Carbon monoxide	50 ppm	300 ppm
Copper fume	0.2 mg/m 3

 

If the fume contains only substances such as iron or aluminium which are of low toxicity, an 8 hour (TWA) OES of 5mg/m3 applies; this figure is the average concentration of particulate fume that should not be exceeded in an 8 hour day. 

* Control of Substances Hazadous to Health (COSHH) Regulations.

The Control of Substances Hazardous to Health (COSSH) Regulations 2002 require employers to monitor the safe use of chemicals and hazardous substances at work. It requires them to: control exposure to hazardous substances to prevent ill health both now and any future cumulative effects they may have, protect both employees and others who might be exposed, compile records of employees using these materials, supply employees with suitable personal protective equipment.

 

After reading activity

 

Think of Russian equivalents for the following word combinations from the text:

Innermost parts of the lung, fuel gas, fine particles, respirable fraction of particles, carbon dioxide, ultraviolet radiation, galvanised steel, lasting effects, welding situations, lung cancer, sensible precaution, surface coating, general population, inadequate ventilation, risk of the build up of inert shielding gases, incomplete combustion, occupational exposure limit, to cause harm to a person's health. 

 

Speaking

 

True or false?

 

1. The smaller the particles the more harmful the fume is.

2. The risk to the welder's health from fume or gases depends on the welding arc.

3. Welders have lung cancermore oftenthan the general population.

4. Asphyxiation may happen due to inadequate ventilation.

5. Metal fume fever is an incurable illness.

 

Fill in the gaps in the following sentences or complete them:

 

1. Argon is a … gas.

2. Particulate fume is very … for man’s health.

3. When exposed to particulate fume of high concentration for a long time, a welder may ….

4. Welding galvanised steel may cause ….

5. Asphyxiation may happen due to ….

6. To minimise the risk, special attention should be paid to controlling fumes which may contain chromium or … compounds.

7. In case of metal fume fever, …. recovery occurs soon after removal of the welder from the exposure.

8. … is a disease caused by fluid on the lungs.

9. MEL means maximum … limit.

10. OES is … exposure standard.

11. Gases encountered in welding are ….

 

Answer the following questions:

 

1. What is the difference between welding fume and welding gas?

2. What does the major part of the particulate fume arise from?

3. What does the degree of risk to the welder's health from fume or gases depend on?

4. Under what condition is control over the exposure of welders to hazardous fumes or gases considered adequate?

5. Do the COSHH Regulations state only single substances?

 

Vocabulary

bare spot	оголенный участок
wire feeder	механизм подачи (электродной или присадочной) проволоки
ground connection	1) заземление, замыкание на землю 2) соединение на корпус
power switch	переключатель мощности
rupture	а) пробой (изоляции) б) излом, разрушение, разрыв
confined space	замкнутый объём, замкнутое пространство
exhaust hood	вытяжной шкаф; вытяжной колпак

 

Reading