Fire-reserve water sizing on a hospitality site is a regulatory calculation, not an engineering preference. SANS 10400-T (the fire-protection part of the National Building Regulations) sets the requirement: a dedicated fire-water reserve sized to a defined duration at a defined flow, with a registered engineer's signature on the calculation (SABS, 2011). Insurance underwriters increasingly request that signature before binding.
The three inputs
- Occupancy class. SANS 10400-A defines the classes — hospitality occupancy is generally A2 (entertainment and public assembly) with sleeping accommodation in A3. Each class has its own design-fire scenario.
- Building height and area. Determines whether the site requires fire hydrant systems (yard hydrant or building hydrant), sprinkler systems, or both. Most luxury lodges fall below the sprinkler threshold but require external hydrant coverage for thatched roofs.
- Building construction. Thatched roofs trigger a substantial uplift in fire-water reserve requirement. A 20-suite lodge with thatched suites can require 30–80 m³ of dedicated fire reserve at 30 L/s for 1–2 hours — significantly above what the casual quote presumes.
The pump pair
The fire-pump configuration on most lodges is an electric main duty pump (typically 30 L/s at 70 m head, axial-split case or vertical multistage), a diesel standby of equivalent rating, and a small electric jockey pump (1.5 L/s) maintaining standpipe pressure. Auto-start logic on pressure drop; manual-stop only. SANS 10287 governs the pump set certification (SABS, 2014).
What gets missed
- Dedicated reserve. The fire reserve is dedicated. The same tank cannot be the potable storage. It must be a separate compartment, plumbed only to the fire mains, with a low-level alarm to the fire panel.
- Hydrant accessibility. Hydrants must be reachable by the local fire-service appliance with a 60 m hose run. On large lodge sites this often means multiple hydrant points and a ring main, not a single hydrant at the gate.
- Annual testing. The fire pumps must be tested under load monthly, and the entire fire-water system pressure-tested annually. The test reports go into the same compliance binder as the SANS 241 file.
The cost of doing this right is meaningful. The cost of an underwriter declining a claim because the fire-reserve calculation carried no engineer's signature is generational.
