Modern Building Services

FIRE SAFETY R iser shafts feature so prominently in high rises, yet when it comes to understanding what they are and why they are needed from a fire protection perspective, there are misconceptions that obscure the truth. There are, for example, problematic misunderstandings in relation to fire protection rules during and post-construction and the difference between intumescent paint and fire encasement. Alex Bardett Managing Director of Ambar Kelly – a manufacturer of a riser zone solution – sets these misconceptions straight, stressing the importance of greater education on riser zone fire safety. The big issue Riser shafts are a fundamental presence essential to building operation. Yet, in terms of their design and construction, there are two big misconceptions that need to be addressed. The first relates to the differences between fire protection rules and codes of practice during construction (i.e., HSG 168 and the Joint Codes of Practice) and regulations post-construction. Approved Document B of the Building Regulations covers fire safety matters within and around buildings. Both need to be adhered to, but the former is little understood and generally ignored. In order to assure safety, the design of the riser shaft has to be undertaken meticulously in accordance with Approved Document B. The riser shaft is typically encapsulated within a two-hour fire wall around it. The doors into that shaft need to offer one-hour protection. The shaft itself can vertically be any number of floors from 2-50; the design standards don’t specify any details regarding temporary protection required during construction. It would need to be horizontally fire protected where it goes into different fire compartmentations, which may be at basement level 1 or the 50th floor into the plant room. The horizontal fire protection must be supported off of materials which are Class A2 or better. Wherever the fire compartmentations are there would need to be two-hour horizontal fire protection, i.e., a floor of 2-hour fire resistance. At this stage, it is the architect’s responsibility to design to these standards so that fire 34 MODERN BUILDING SERVICES OCTOBER 2021 By Alex Bardett , Managing Director of Ambar Kelly Education at the core of demystifyingRisermisconceptions FEATURE FIRE SAFETY