BS 9999:2017 — Fire safety in the design, management and use of buildings

What it is for

BS 9999 is a code of practice covering fire safety across the whole life of a building — how it is designed, how it is managed once occupied, and how it is used. Its distinguishing feature is that it works from a risk profile rather than a fixed set of dimensions: the occupancy characteristic and the fire growth rate of a building determine what is required of it, so a building with alert, mobile, familiar occupants and a slow-developing fire risk is treated differently from one where none of those hold.

That makes it a more flexible route than the prescriptive guidance in the Building Regulations documents, and it allows trade-offs — better detection buying additional travel distance, for example — that a purely prescriptive approach does not.

Scope and typical application

It addresses buildings other than dwellings. In practice that means offices, shops, places of assembly, industrial premises, education and healthcare buildings, and the non-residential parts of mixed-use developments. It is not intended for single-family homes, and residential buildings have their own code of practice in BS 9991.

Two typical uses. In design, as an alternative to the Building Regulations guidance where the prescriptive route is too restrictive for the building being proposed. And in the management of existing buildings, where its material on evacuation strategy, maintenance regimes, fire safety management and the ongoing upkeep of fire protection measures is directly useful to anyone responsible for a building already in use.

That second use is the one most relevant to fire risk assessment. When an assessment asks whether the existing means of escape, detection and compartmentation are adequate for the way a building is actually occupied, BS 9999 is very often the benchmark being applied.

How it relates to legal duty

A British Standard is not law, and BS 9999 has no direct statutory force. Its relationship with legal duty runs through two routes.

For new work, compliance with the Building Regulations can be demonstrated either by following the Approved Document guidance or by another route that meets the functional requirements — and BS 9999 is a recognised such route. Choosing it is a design decision to be agreed with building control, not a unilateral one.

For buildings in use, the Regulatory Reform (Fire Safety) Order 2005 requires a suitable and sufficient fire risk assessment and adequate general fire precautions, without specifying standards. BS 9999 supplies the technical benchmark against which "adequate" is commonly judged. It informs the answer; it does not supply the duty.

What this means in practice

A common error is to treat BS 9999 and Approved Document B as interchangeable menus to pick from clause by clause. They are alternative routes, each internally coherent, and the trade-offs in BS 9999 only work if the risk profile that justified them is real and remains real. A building assessed on the basis of alert, familiar occupants and then let to a different kind of tenant has lost the premise its arrangements rested on.

Status and currency

BS 9999:2017 was published on 31 January 2017 and remains current. Corrigendum No. 1 was issued in February 2017.

A revision project is open at BSI under the designation BS 9999:202x. It is at an early stage: the material published so far describes items under consideration, explicitly not agreed, and no draft for public comment has been issued. Nothing about that project changes the standing of the 2017 edition today, but anyone specifying against BS 9999 for a long-running project should keep it in view.