SANS 10400 is the family of national standards that puts the National Building Regulations into technical practice. Each part covers one topic, and the parts work as deemed-to-satisfy rules: build to the part and you comply with the matching regulation. Here is what each part means for a working contractor, plus the two plumbing standards (SANS 10252 and SANS 10254) that ride alongside it.
The parts that matter on site
- Part A: general principles. Definitions, occupancy categories (classes A to G) and the plan-submission framework. Every other part hangs off the occupancy class, so know yours before pricing.
- Part B: structural design. Foundations, floors, walls and roofs must handle dead, live, wind and seismic loads. If you are not an engineer, stay inside Part B's prescriptive rules or bring in a structural engineer. There is no third option.
- Part L: roofs. Minimum slopes per material, fixing requirements, eaves and barge details, weatherproofing laps. Roof details are the most common plan-approval non-conformance for small builders.
- Part P: drainage. Sanitary and stormwater drainage, traps, minimum gradients, rodding eyes and venting. The plumber's daily bread.
- Part T: fire protection. Fire-resistance ratings, compartment sizes, travel distances and exit widths. The current edition is SANS 10400-T:2020, which replaced the 2011 edition. Buildings outside its prescriptive limits need a rational fire design (see the fire compliance guide).
- Part W: fire installations. Sprinklers, hose reels, detection and extinguishers, triggered by the Part T occupancy class and floor area.
- Part XA: energy efficiency. Mandatory for new buildings and additions needing plan approval (garages and storage excepted). At least 50 percent of annual domestic hot water demand must come from energy-efficient means, with prescriptive, performance or reference-building compliance routes.
- Part X: environmental sustainability. The broader sustainability framework supporting XA.
The two plumbing standards next door
- SANS 10252: water supply installations. Pipe sizing, materials, water pressure, pressure-limiting and pressure-reducing valves, isolation valves.
- SANS 10254: hot water cylinders (geysers). Positioning, supports, drain and overflow pipes, thermostats and the pressure control valve (PCV). The standard now requires balanced pressure: the PCV moves to the main supply feeding the whole property, not just the geyser's cold inlet, so hot and cold pressures are equalised. Geyser installs that miss this fail compliance inspections.
A worked example: the kitchen extension
A 20 m2 kitchen extension touches Part A (occupancy class), Part B (slab and walls), Part P (new waste connections), Part L (the new roof section) and Part XA (roof and wall insulation). Add a skylight and Part T can be engaged for rooflights in certain occupancy classes. The building control officer must be satisfied on all of them before approval, which is why "it is only a kitchen" extensions stall at plan stage.
Where to get the standards
Individual SANS 10400 parts are sold by the SABS; they are not free. Editions change, and Part T already has: always check you are working from the current edition before relying on a detail, because an inspector or a BCO will be working from the current one.
Common mistakes
- Pricing before checking the occupancy class. Class drives fire, exits and compartment rules, and therefore cost.
- Structural improvisation. Outside Part B's prescriptive rules, you need an engineer, not experience and optimism.
- Geyser PCV on the cold inlet only. Balanced pressure on the main supply is the current requirement.
- Working from an old edition borrowed from another job's file.
- Forgetting Part XA on additions. Energy efficiency applies to extensions needing plan approval, not just new builds.
Know someone who needs this?
Keep reading
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? SADAG 0800 567 567 ·