With effect from 1 January 2006, revised procedures covering the testing and certification of boilers came into effect. This guidance note highlights the salient points of these procedures but it does not cover every detail. The full procedures are available for inspection at the Track and it is the responsibility of members who construct or operate boilers to familiarise themselves with the requirements.
The procedures as set out below are applicable to copper boilers up to and including 500 bar litres.To obtain the capacity of a boiler the working pressure in bars is multiplied by the volume in litres – e.g. a boiler working at 5 bars with a volume of 4 litres has a capacity of 20 bar litres. (1 bar = 14.5 p.s.i. 1 litre = 1.76 pints)
FREQUENCY OF TESTS
Under the new procedures the following tests are required:-Hydraulic Test: On a new boiler and subsequently every 4 years
Cold Visual Inspection: On a new boiler and subsequently annually
Steam Test: On a new boiler and subsequently annually (there is no period of grace beyond the expiry date on the certificate)
COMMERCIALLY BUILT BOILERS
Where a member has purchased a new boiler which has been manufactured and hydraulically tested by a recognised commercial manufacturer, the manufacturer’s certificate for a hydraulic test to twice the working pressure will be acceptable as proof that the structure of the boiler has satisfied the requirements for the hydraulic test.
A visual examination, a hydraulic test with fittings in place to 1-1/2 times working pressure and a steam test will still be required before the boiler can be certified for use. Boilers built commercially after 31 May 2002 and not having a CE mark shall not be tested.
When a boiler has been built to a published design no further verification of design calculations will be required. The member will be required to submit drawings and calculations to prove adequate margins of safety if;
- The boiler is not to a published design
- The boiler incorporates changes to a published design
- The working pressure has been increased above that shown on the published drawings
- No working pressure is shown on the published drawings
The regulations also specify other design features which shall be applied to new construction :-
- A boiler shall have at least 2 independent means of water feed e.g. axle pump, hand pump, 2 injectors. However feed requirements for boilers under 3 bar litres can be via a Goodall valve or the capacity of the gas tank must be such that the fuel must run out before the boiler is empty of water (below the lower nut on the water guage glass).
- Valve spindles shall be captive on new boilers from 1 Jan 2011 – a TSMEE requirement.
- Water gauges shall be independent of any other fittings ( e.g. not taken from the manifold )
- Pressure gauges should have a full scale reading at least 30% above Working Pressure.
- Pressure guages must be marked with a red line at the maximum working pressure
All prospective builders must contact the boiler testers before beginning construction to agree possible requirements and the testers shall be given the opportunity of examining a boiler at least twice during its construction. This is to facilitate the inspection of joints which may not be visible when the boiler is complete. The frequency of intermediate examinations will be agreed during initial discussions.
Boilers will be subject to a visual examination with all fittings in place. A boiler will be examined visually prior to each hydraulic test. Subsequent annual visual examinations will take place prior to steam tests annually. The examination will check for defects such as: Mechanical damage; Wasting; Loose fittings; Inoperable valves; Evidence of leaks.
A new boiler must be hydraulically tested to twice its working pressure. The initial hydraulic examination must be undertaken without cladding or lagging in place.
Subsequent hydraulic tests are required at intervals not exceeding 4 years. The subsequent tests are to one and a half times the working pressure and may be conducted with lagging and cladding in place.
As part of the hydraulic test procedure the pressure gauge will be tested against the certificated test gauge. The boiler’s pressure gauge must be accurate at the working pressure. The gauge must be clearly ‘red lined’ at the maximum working pressure.
The test pressure must be sustained for at least 10 mins. and any loss of pressure must be accounted for.
At the satisfactory completion of the initial hydraulic test a boiler will be allocated an identification number. This number to be stamped on the boiler in a location where it will be visible when the boiler is in use.
A steam test will be conducted on a boiler when new, then annually. The examination will include verification of the following :-
- Correct operation of at least two independent feed systems
- Operation of safety valves at correct pressure
- Ensuring blower is not capable of raising boiler pressure by more than Working Pressure + 10%
- Correct operation of gauge glass(es)
- Correct operation of pressure gauge.
When a boiler has been subject to structural repair or modification it will be considered as a new boiler for testing procedures.
The regulations permit the examiner to vary the test requirements where he considers this to be appropriate.
It would be appreciated if members give notice to the boiler inspectors when tests are required.