When I did a job similar to this I referred to the following documents.
The HSE website (
http://www.hse.gov.uk/fireandexplosion/petroleum-faqs.htm) (11) states that:-
"There are no specific legal requirements on how to store diesel or the quantity allowed either in workplaces or domestic premises. It is not, from a health and safety point of view, a particularly hazardous substance within the meaning of the Dangerous Substances and Explosive Atmospheres Regulations 2002 - its vapour flash point is too high. This means that its vapour will not ignite at normal room temperatures."
"The DSEAR Regulations do not normally regard diesel fuel as a dangerous substance. This is because its flash point is fairly high and therefore not considered as a flammable substance within the meaning of the CHIP regulations (DSEAR uses the definitions in CHIP to define dangerous substances). The flash point of diesel is much higher than the normal ambient temperatures experienced in GB. However, if diesel fuel or the vessel in which it is contained is heated to a point beyond its flash point (about 60C), then it is covered by DSEAR. Thus, for example, hot-work (welding or cutting etc) should not be undertaken on a tank or container which contains diesel until the tank or container has been completely emptied and gas-freed as otherwise there is a serious risk of a fire or explosion. In some respects, diesel leaks and spills present more of a hazard to the environment than health and safety".
The flash point for diesel fuel varies with the manufacturer - the HSE state it is generally within a band from 60-90deg C.
The following National and International Guidance documents were considered in my job.
1. The Building Regulations 2012 Approved Document J6.
2. Guidelines for the Construction of Fire Resisting Structural Elements, Morris, W.A. et al. The Building Research Establishment, Garston, Watford, WD2 7JR.
3. Recommendations for Fire Safety in the Storage of Highly Flammable and Flammable Liquids - Part 1 General Principles RC20 part 1. The Fire Protection Association.
4. Risk Control - Storage and Use of Highly Flammable and Flammable Liquids in External Storage Tanks RC57. RISC Authority.
5. The National Fire Protection Association (USA) NFPA30 (2012) Section 22.4.1 - Storage of Liquids in Tanks - Above Ground Storage Tanks.
6. GAPS Guidance 2.5.2 Table 3.
7. FM Global Property Loss Prevention Data Sheets 7.88 - Flammable Liquid Storage Tanks.
8. Northern Ireland Fire Safety Guidance Note 8 - Provisions for Oil Fuel Storage and Supply.
9. Material Safety Data Sheet - Diesel Fuel Oil - Nationwide Fuels.
10. Oil Fired Technical Association (OFTEC) guidance OFT 200.
11. HSE website
http://www.hse.gov.uk/fireandexplosion/petroleum-faqs.htm.
12. BS EN 12285-2.
13. Control of Asbestos Regulations 2006 - HSE Publications - L127 - Approved Code of Practice and Guidance.
UK Guidance
1. Recommendations for Fire Safety in the Storage of Highly Flammable and Flammable Liquids - Part 1 General Principles RC20 part 1. The Fire Protection Association, and
2. Risk Control - Storage and Use of Highly Flammable and Flammable Liquids in External Storage Tanks RC57. RISC Authority.
For guidance on the installation of large tanks Approved Document J suggests that advice should be sought from the local Fire and Rescue Service. I have researched the advice of fire services and found the document produced by the Northern Ireland Fire Brigade to be typical, and effectively replicates the OFTEC guidance OFT200
Oil Fired Technical Association (OFTEC) Guidance OFT 200
OFTEC guidance for non-domestic tanks recommends that tanks above 3500 Litres capacity should be located a minimum of 6m from buildings and if this cannot be achieved walls or barriers which extend 900mm beyond each applicable face of the tank should be used. The walls or barriers should have a 2 hour standard of fire resistance.
FM Global Property Loss Prevention Data Sheet 7.88
The FM Global Loss Prevention Data Sheet 7.88 is applied internationally by many insurance companies. The document is more wide ranging and comprehensive than the RC57 and RC20 documents produced in the UK and unlike the UK guidance the scope includes liquids with a flash point over 55degC such as diesel oil. It also recognises a wider range of tank and construction approaches and especially for those tanks with additional safeguards compliant with BS EN 12285-2. (See page 8 paragraph 6 of the guidance).
The guidance recommends that secondary containment tanks with a capacity of up to 45000 Litres, meeting the requirements of BS EN 12285-2, that are used for diesel fuel, sited a minimum of 1.5m from building walls or openings and are protected against impact damage by vehicles, and provided with overfill and anti-siphon devices do not need any further precautions to be taken to protect the building from a fire in the tank, and vice versa.
NFPA Guidance
The National Fire Protection Association (USA) NFPA30 (2012) Section 22.4.1 - Storage of Liquids in Tanks - Above Ground Storage Tanks.
This guidance document recommends that tanks with a capacity of up to 45m3 should be sited a minimum distance of 5 ft. from a building.
GAPS Guidance
The NFPA 30 guidance is re-iterated by GAPS Guidance 2.5.2 Table 3.
Hope this helps
