LPG bulk tank compound at a village restaurant
A village restaurant in Tai Po proposes two 1,000 L LPG storage tanks to replace cylinder supply. The compound is 5 m from the kitchen wall, 7 m from a neighbour's village house and 2 m from a public footpath. It is enclosed by a 1.8 m chain-link fence, has no bund, and the surface drain runs to a stormwater channel. Tanker access is a 2.5 m wide lane with a 35 m hose route to the tanks. The relief valve outlet is 2 m above ground and discharges toward the kitchen. Peak demand is 12 kg/h; the restaurant wants to keep 10 days' stock and refill fortnightly. The contractor's drawing shows one 25 mm vapour line and no emergency shut-off valve at the tank compound. The landlord has already built the concrete plinths.
1. Identify the main hazards and code issues, and decide whether the layout is acceptable as drawn.
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The main hazards are a large flammable inventory, LPG being heavier than air and able to travel along drains, and ignition of a leak at grade or in the compound. Two 1,000 L tanks at 80% fill contain about 1,600 L of liquid; at roughly 0.51 kg/L that is about 816 kg of LPG, far more than a cylinder bank. The layout is not acceptable as drawn: no bund means a leak can spread; the surface drain to stormwater gives a preferential path for vapour; 5 m to the kitchen and 7 m to a village house must be checked against the code's separation/radiation requirements, not accepted by eye; a chain-link fence gives no fire resistance; the relief valve discharging toward the kitchen is wrong; and there is no emergency shut-off at the compound. The 2 m footpath and 2.5 m lane also affect emergency access. The decision should be 'not approved pending redesign', with the tank size reduced or relocated if the required separation cannot be achieved.
2. Evaluate the relief valve arrangement and tanker access, and state what must change.
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The relief valve must be sized for fire exposure and discharge freely upward or to a safe location away from buildings, air intakes, windows, footpaths and the tanker route; it must not be capable of being isolated by a valve that could be left closed. A discharge 2 m above ground toward the kitchen is unacceptable because heavier-than-air vapour can reach the kitchen and ignition sources. Tanker access must allow the vehicle to stand safely, set the handbrake, use wheel chocks, bond before transfer, and reach the tank connection with a hose route that does not pass through the kitchen or public footpath. A 35 m hose route and 2.5 m lane need formal review; if the lane is the only fire-service access, the installation may be unacceptable. Provide a dedicated hardstanding, emergency shutdown at the tanker connection and at the compound exit, and a written transfer procedure.
3. Recommend risk controls and the regulatory path before any LPG is introduced.
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Recommend: reduce inventory (e.g. one smaller tank plus cylinder backup) or relocate the compound to achieve the required separation; provide a bund with capacity for the largest tank and a trapped drain with a valve, not a direct storm connection; grade the compound so spills stay inside; replace the chain-link with a fire-resistant wall/fence where required; re-route the relief valve discharge; fit an emergency shut-off valve at the compound entrance and at the tank; provide gas detection, signage, fire extinguishers and no-smoking controls; and formalise tanker access and transfer. Submit revised drawings to the gas authority and Fire Services Department as required, update the licence/notifiable installation, and commission with pressure/tightness tests, relief valve checks and operator training. The plinths already built do not justify retaining an unsafe layout; they may have to be broken out. No LPG should be introduced until the revised layout is approved and the emergency plan is tested.