Ventilation
Welding rods used for manual metallic-arc-welding are usually coated with a fl ux (the reason for this will be explained in Chapter 10). Fume extraction is essential to remove the fumes given off by the hot fl ux. This should be designed so that the fumes are not drawn upwards passed the welders face. Adequate general ventilation should also be provided. The fl ux solidifi es to leave a hard coating of slag over the weld zone that needs to be chipped off. When chipping, clear goggles must be worn for eye protection as discussed in sections 1.9.2 and 1.10.4.
Figure 1.51 Overhead platforms
Figure 1.52 Use of a static safety block
the wire rope mounted on a spring-loaded drum unwinds or winds up automatically, keeping the rope taut but not hindering the user. In the event of a slip or fall, a friction brake engages automatically and the fall is stopped safely after about 300 mm with no jolt or jerk.
Figure 1.53 The self-contained safety block
Figure 1.54 The use of self-contained safety blocks
Exercises
1.1 Health and Safety at Work Act and other important industrial legislation
a) i) What do the initials HSE stand for?
ii) What is a prohibition notice?
iii) What is an improvement notice?
iv) Which person is responsible for issuing the notices in questions i) and ii) above?
b) As an employee you also have duties under the Act. Copy out and complete Table 1.6 by writing brief comments regarding your duties in the fol- lowing circumstances.
c) Copy out and complete Table 1.7 by adding the name of the most appropriate industrial regulation(s) for each of the situations given.
d) Copy out and complete Fig. 1.55 by stating:
i) The category of the sign (e.g. warning sign, mandatory sign, etc.).
ii) The meaning of the sign.
iii) Where the sign should be used.
1.2 Electrical Hazards
a) Explain why portable electrical equipment should be:
i) Earthed unless it is ‘ double-insulated ’ . ii) Operated from a low-voltage supply.
iii) Protected by an earth leakage isolator incorporating a residual current detector.
b) When you are issued with portable elec- trical equipment from the stores you should make a number of visual checks before accept- ing and using the equipment. Describe these checks.
c) If the checks you made in b) above showed the equipment to be faulty, what action should you take?
d) In the event of a workmate receiving a severe electric shock that renders him/her unconscious, what emergency action should you take?
Table 1.6 Exercise 1.1(b)
Circumstances Duties
You are uncertain how to operate a machine needed to complete your task
You need to carry some sheet metal with very sharp edges
You are working on site and you have mislaid your safety helmet You fi nd that the belt guard has been removed from a machine you have
been told to use
You have spilt hydraulic oil on the fl oor whilst servicing a machine The earth wire has come disconnected from a portable power tool you are using Your supervisor has told you to clear up the rubbish left by another worker
You fi nd someone smoking in a prohibited area
Table 1.7 Exercise 1.1(c)
Situation Appropriate industrial regulations
Use of grinding machines and abrasive wheels Eye protection
Electrical control equipment, use and maintenance Use of substances that can be harmful to health (solvents, etc.)
Safe use of power presses
Protection against high noise levels
Safe use of milling machines
Use of protective clothing
1.3 Fire hazards
a) List THREE main causes of fi re on industrial premises.
b) If you detect a fi re in a storeroom at work, what action should you take?
c) Figure 1.56 shows some various types of fi re extinguisher.
i) State the types of fi re upon which each extinguisher should be used and any precautions that should be taken.
ii) State the colour coding that identifi es each type of fi re extinguisher.
1.4 Accidents
a) Why should all cuts, bruises and burns be treated by a qualifi ed fi rst-aider, and what risks does a well-meaning but unqualifi ed person run in attempting fi rst aid?
b) Apart from rendering fi rst aid what other action must be taken in the event of an accident?
c) State how you would identify a fi rst aid post.
d) What action should you take if you come across someone who has received a serious accident (broken bones, severe bleeding, partial or com- plete loss of consciousness, etc.)?
Figure 1.55 Exercise 1.1(d)
e) Briefl y describe the accident reporting procedures for your place of work or training workshop.
1.5 Working environment
a) Copy out and complete Table 1.8 by stating the type of working environment in which you would need to use the following items of safety clothing and equipment listed in the table.
b) With the aid of a sketch explain what is meant by:
i) A transmission guard.
ii) A cutter guard.
c) For each of the examples listed below, sketch an appropriate item of safety equipment and state how it works.
i) A drill chuck guard.
ii) A chipping screen.
iii) An interlocked transmission guard.
1.6 Lifting and carrying
a) State the maximum recommended weight that may be lifted without the aid of mechanical lift- ing equipment.
b) With the aid of sketches show the correct and incorrect way to lift a load.
c) What precautions should be taken when carrying loads?
d) What precautions should be taken when moving a heavy load with a lifting team?
e) Lifting equipment should be marked with its SWL.
i) State what these initials stand for.
ii) State how often lifting equipment needs to be tested and examined.
iii) State what records need to be kept.
Figure 1.56 Exercise 1.3(c)
Table 1.8 Exercise 1.5(a)
Clothing/equipment Situation/environment
Ear protectors Overalls PVC apron Leather apron Leather gloves PVC/rubber gloves Safety helmet Clear goggles Visor Barrier cream Safety boots
Goggles with fi lter lenses
1.7 Oxy-acetylene welding
a) State how you would distinguish between oxygen and acetylene cylinders.
b) List THREE important precautions that should be taken when handling welding gas cylinders.
c) Explain briefl y how to test for leaks in oxy-acet- ylene welding equipment.
d) Explain briefl y the fi re and explosion hazards associated with oxy-acetylene welding equip- ment and how such hazards can be avoided.
e) Describe what essential protective clothing and equipment should be worn when oxy-acetylene welding and fl ame-cutting.
1.8 Electric arc-welding
a) What is the most dangerous hazard associated with the primary (mains) circuit of electric arc- welding equipment? Explain what steps can be taken to minimize this hazard.
b) Briefl y describe the precautions that should be taken to minimize any hazards associated with the external (secondary) electric arc-welding circuit.
c) Describe what essential protective clothing and equipment should be worn when electric-arc welding.
d) Explain what is meant by ‘ arc-eye ’ and explain how this condition can be treated.
e) Explain why good ventilation is essential when arc-welding with coated electrodes.
1.9 Working on site
Describe the hazards likely to be faced when work- ing on site compared with working in a factory environment. Pay particular attention to climbing, working at heights, craning and lifting, protective clothing and personal safety equipment.