Why are gas hoses different colours?
The hose assembly provides a flexible connection between the pressure regulator, safety devices and the process equipment. It consists of a flexible hose with a hose connection inserted into each end, suitably secured.
Each hose assembly shall (must) be compatible with the gas with which it is to be used. Hose assemblies shall (must) not be used for gases or at pressures other than those for which they have been designed, which is why they are colour coded.
- Blue hose – Oxygen
- Red hose – Acetylene and hydrogen
- Orange hose – LPG, methane and natural gas
- Black – Inert gases (compressed air, nitrogen, argon and carbon dioxide)
Do gas hoses have an expiry date like regulators and flashback arrestors?
No.
Hoses are probably the item of a compressed gas system that will receive the most abuse and wear, and, as in the case of oxy-fuel gas systems, are likely to be employed in the most aggressive working conditions.
Compressed gas hoses are seamless flexible tubes designed to carry one or a number of specified gases.
The hoses usually consist of an inner extruded tube, with a means of reinforcement – this may consist of a number of layers – and an outer cover (usually rubber).
When they are worn, damaged or contaminated, they must be replaced.
How often do I need to inspect my hoses?
Hoses should receive a visual inspection each time prior to use.
If any damage or contamination is found, then the hose must not be used and should be replaced immediately.
Hoses should receive a full inspection, which includes functional tests, at least annually, or more frequently if identified in your risk assessment.
This inspection should be undertaken by a competent person, and written records should be kept.
Can I make up my own hose assemblies?
No..not unless you can test your assembly in line with the relevant British or European standard.
A hose assembly consists of a flexible hose with a hose connection inserted into each end, suitably secured.
BCGA CP47 states that hose connections shall (must) be secured using suitable clamps, for example, clips or ferrules.
If my hose is worn or damaged, can I cut out the damaged section and then re-fit the connection using a worm drive screw?
Localised repairs should not be carried out. Where a repair is carried out, then the hose shall (must), as a minimum, meet the specification set by the original manufacturer. The correct style of hose-splicer and associated fittings shall (must) be fitted.
Following a modification or repair, the hose assembly shall (must) be re-tested and certified to BS EN 1256.
Following any local repairs, the owner of the hose will assume full responsibility for its fitness for service.
BCGA Codes of Practice state that ‘A hose assembly shall (must) not be secured using worm drive clamps’.
If I’m using an oxy-fuel gas system, can I tape my hoses together?
No.
BCGA CP7 states:
‘Do not tape hoses together.
Tape can cover damage to the hose’s outer layer.
To reduce trip hazards, hoses can be joined together by hose clips (plastic or metal) specifically designed for that purpose.
Conjoined hoses (known as Siamese hoses) can be used provided that the hose and the assembly conform to the required standards.
It is important to remember that failure in one hose can lead to failure in the other and lead to a potentially more hazardous situation.’
Why are the connectors on each end of my oxygen hose slightly different?
The majority of oxy-fuel gas hoses supplied in the UK have a standard connector at one end and a non-return valve, known as a hose check valve, at the other end.
Ths hose check valve must be fitted to the torch inlet.
Will a hose check valve stop a flashback?
No.
A hose check valve is designed to stop gases back-feeding up the hoses.
It does not contain a flame-arresting element and is not designed to stop a flashback.
So, you need a hose check valve at the torch end of your hose and a flashback arrestor connected to your regulator at the cylinder end of your hose.
