S15 Health and safety

Posted: October 10, 2010 in Systems and Control

I need to look closely at health and safety within systems and control.  Extreme vigilance must be taken, BS4163 and CLEAPSS need to be examined (see health and safety resistant materials) and due care and attention taken at all times.

SOLDERING IRON

I have used this tool to solder the components onto my PCB.  I have used this tool before safely and was able to conduct a safe practise again, although my soldering left a lot to be desired in the first few attempts.

BS4163 Main points:
Hazards: Electric shocks.  Leads that can be tripped over.  The  hot soldering iron tip is hot enough to burn.  Fumes from rosin based fluxes can cause respiratory sensitisation.  Melted solder or flux could burn if in contact with the user.

Suitable materials and processes:
To help create a joint between 2 faces of sheet metal or to create a connection between wires and its terminals using molten solder with a flux

PPE
Protective glasses, use in a well ventilated room

CLEAPSS Main points:
Hazards:  There is a possible hazard of an electric shock via the bit to the metal being soldered ( this is because it is hard to provide insulation between the bit and the element without reducing heat conduction).  The mains cable could also be vulnerable to damage from the hot tip of the iron.  Although I did not use one, the gas heated types could be a fire hazard because of the butane fuel.  There is a hazard of burning as the tip and the stem of the iron get hot enough to burn skin.

Risk assessment:  Burns from soldering are usually minor but can be easily avoided.  Circuit components are more likely to be damaged than the person using the iron.  Heat damage to a mains lead is a high risk.

Common problems:
Stray bits of solder or splashed solder can burn.  The tip of the soldering iron must be kept clean to provide a more accurate result.  Soldering must take place in a well ventilated room.  The iron must be kept in its rest when not in use, not on the table.  Soldering does not provide a very strong mechanical joint.  Care must be taken to avoid any short circuits.

PCB ETCHING

I have observed this machine when making my pcb for the ambiance light.

BS4163 main points: Ferric chloride is an irritant and can be harmful.  Sodium persulfate is an irritant and an oxidizing agent.

Risk assessment: It is essential that protective goggles and gloves are worn when preparing ferric chloride solution and when emptying tanks.  Any contact with skin should be avoided and if contact does occur should be washed off immediately.

CLEAPSS main points: Ferric chloride and sodium persulfate are harmful if swallowed, although not classed as this it can cause dizziness and headaches if consumed.  Toxic, if the two etchants are mixed a toxic chlorine gas is produced.  Irritant, solid etchings or solutions can be an irritant to the skin or the respiratory system.  Sodium peroxdisulphate is highly flammable, it releases oxygen when wet which can enhance fire.

PPE: Protective gloves and goggles

Risk assessment: Solid sodium peroxdisulphate is harmful so measures must be taken to avoid indigestion.  If applied with a brush these concentration will not be approached, even locally in a school electronics area.  If the two etchants are used in the same area there is a possibility of them being mixed deliberately or by accident.  Sodium peroxdisulphate can create a mist which makes it less suitable for a bubble etch tank, if used in a small manual developing tray though minimal mist is produced.  The presence of sodium peroxdisulphate does not enhance the fire risk.

To dispose of solid waste it should be put in appropriate containers and consigned to an authorized contracted waste disposal.  Used sodium hydroxide should be neautralised with 1 M ethanoic acid before pouring away.  A siphon pump is recommended to empty tanks and great care must be taken when doing so.  To store the substances they should be placed in a secure, dry, well ventilated area and ferric chloride should be kept away from metals.

The tests I have done with a multimeter have all been on low voltage circuits and they cannot hurt you too much but it is worth noting that if it was necessary to test a high voltage then careless use of the multimeter would cause serious harm.  Even if not actively testing a high voltage circuit dangerous current can be exposed and it is important to remember to keep your fingers away from the metal tips of the meters test leads.


		
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s