3.23 Fuel storage – protection from fire
The guidance on oil relates only to its use solely where it serves a combustion appliance providing space heating or cooking facilities in a building. There is other legislation covering the storage of oils for other purposes. Heating oils comprise Class C2 oil (kerosene) or Class D oil (gas oil) as specified in BS 2869: 2006.
It is considered unlikely that a fire will originate from the stored oil. It is the purpose of this guidance therefore, to ensure that a fire that may originate from a building, or other external source, is not transferred to the tank contents, or if a fire does occur, its effects are limited.
The acceptance of climate change and the environmental policies put in place to mitigate its impact are pushing the commercial introduction of renewable energy technologies to displace the use of fossil fuels and the related combustion emissions of greenhouse gases. Woody biomass can be used as an alternative to fossil fuels and in some EU countries biomass fuel is the principal source of renewable energy for heating applications. The carbon dioxide emitted when biomass is burnt can be considered to be offset by the carbon dioxide absorbed as trees grow. Whilst this does not compensate for the energy used in processing the wood for fuel, the carbon dioxide emissions are considerably less than those of fossil fuels.
The use of woody biomass, in the form of wood chips, wood pellets and logs may offer a viable alternative to fossil fuels, particularly in areas not served by the gas grid, although the supply and distribution of chips and pellets is, as yet, still developing with increasingly more suppliers available.
Information of the different types of woody biomass fuel can be found on the BSD website under: ‘Storage of woody biomass fuel for heating equipment’ http://www.scotland.gov.uk/topics/built-environment/building/building-standards
Every fixed oil tank with a capacity of more than 90 litres should be located at a distance from a building to reduce the risk of the fuel that is being stored from being ignited if there is a fire in the building. Some fire protection to, or for, the building is required if the oil tank is located close to the building. Further guidance may be obtained from OFTEC Technical Information Sheet TI/136, Fire protection of oil storage tanks.
Precautions should also be taken when an oil storage tank is located close to a boundary. The installation of a tank should not inhibit full development of a neighbouring plot.
Large tanks - an oil tank with a capacity of more than 3500 litres should be located in accordance with the recommendations in BS 5410: Part 2: 1978.
Small tanks - an oil tank with a capacity of not more than 3500 litres should be located in accordance with the following table:
Table 3.17. Location of oil storage tank not more than 3500 litres capacity
|Location of tank||Protection recommended|
|Building without openings||Building with openings|
|Not more than 1.8m from any part of any building||
|More than 1.8m from any building||non-combustible base|
|Not more than 760mm from a boundary|
|More than 760mm from a boundary||non-combustible base|
|Externally, wholly below ground||no protection required|
The fuel feed system from the storage tank to the combustion appliance is also a potential hazard in the event of fire. The fire valve on the fuel feed, should be fitted in accordance with clause 8.3 of BS 5410: Part 1: 1997 and OFTEC Technical Book 3.
Oil pipelines located inside a building should be run in copper or steel pipe. The recommendations of clause 8.2 of BS 5410: Part 1: 1997 should be followed.
Fire can also spread to an oil storage tank along the ground. Provision should therefore be made to prevent the tank becoming overgrown such as a solid, non-combustible base in full contact with the ground. A base of concrete at least 100mm thick or of paving slabs at least 42mm thick that extends at least 300mm beyond all sides of the tank would be appropriate. However, where the tank is within 1m of the boundary and not more than 300mm from a barrier or a wall of non-combustible construction type 7, short duration (see table to Section 2: Fire, annex 2.B.1), the base need only extend as far as the barrier or wall.
Where a storage tank is located inside a building, additional safety provisions should be made including the following:
the place where the tank is installed should be treated as a place of special fire risk, and
the space should be ventilated to the external air, and
the space should have an outward opening door that can be easily opened without a key from the side approached by people making their escape, and
there should be sufficient space for access to the tank and its mountings and fittings, and
a catchpit as described in the guidance to Standard 3.24.
Guidance on protection from spillage is provided to Standard 3.24.
Further guidance may be obtained from OFTEC Technical Book 3 for garage installations.
By its very nature woody biomass fuel is highly combustible and precautions need to be taken to reduce the possibility of the stored fuel igniting. To ensure maximum energy from the fuel, all storage should be designed to be damp free and improve or maintain the moisture content of the fuel at time of delivery. To inhibit the spread of fire to their contents, bulk storage for wood fuels should be located in accordance with the following table:
Table 3.18. Bulk storage of woody biomass fuel
|Location of container||Protection recommended|
|External and not more than 1.8m from any part of any building||
|External not more than 1m from any boundary||the container or storage frame should be constructed to have short fire resistance duration to its boundary walls|
|Within a building||
Protection for pellets - wood pellets can be damaged during delivery thus producing dust that can cause an explosion and precautions need to be taken to reduce this risk. Once a year any dust that has collected in the store should be removed.
Storage containers for wood pellets, where they are to be pumped from a transporter to the container, should include a protective rubber mat over the wall to reduce the damage to the pellets when they hit the wall. Containers should have an outward opening door incorporating containment to prevent the pellets escaping when the door is opened.
Automated supply - to maintain fire proof storage and prevent back-burning, there should be an interruption to the fuel transport system normally by use of a star-feeder or chute for the fuel to fall into the boiler. The installation should be in accordance with the safety standards described in BS EN 303-5: 1999.
Small installations - delivery of woody biomass fuel in bags would only be economical for small installations such as the suggestion in the guidance to Standard 6.2 for the use of a small woody biomass stove or boiler as secondary heating providing 10% of the annual heating demand. The woody biomass fuel should be stored separately from the boiler that the fuel feeds for fire safety reasons.