Retail / Office Premises Fire Engineering

Background

The owner of a small three storey premises in Petersfield, Hampshire wanted to change the first and second floors to retail floorspace and a stockroom, from existing residential use. The ground floor was already used for retail purposes and would remain so. The Building Regulations application had been refused because it was felt that the functional requirements of Part B1 (Fire Safety) had not been adequately addressed owing to lack of fire protection to a single, unenclosed staircase which served all three floors. The Fire & Rescue Service had recommended that either the staircase be enclosed, or a fire sprinkler system fitted, a view shared by the local Building Control Officer.

The Challenge

Both options presented their own issues: an enclosed staircase would have reduced the usable floor area to an unrealistic level, whilst the cost of installing fire sprinklers would have made the whole project uneconomical.

Knowing Churchesfire’s Fire Safety Engineer Ken Davis from a previous project, the owner approached the company to provide advice. An analysis was carried out to establish the fire safety objectives, identify fire hazards and possible consequences, establish an evacuation strategy and identify acceptance criteria.

The Fire Safety Engineer felt that certain factors warranted further consideration – namely the limited area of each floor, the direct and uncomplicated route to a final exit and the very short overall travel distance from the second floor to a place of safety. He felt that an adequate standard of fire safety could be accomplished without enclosing the staircase or fitting fire sprinklers.

The Solution

A report was prepared in support of a re-submission of the Building Regulations application. A fire risk assessment on the design demonstrated that the original proposals would comply with only minor revisions. Emphasis was placed on calculations which analysed the available safe egress time and compared it with the required safe egress time, clearly demonstrating that a single open staircase serving three storeys provided equivalent safety to a prescriptive approach.

The report – made possible only by the in depth background knowledge of the Fire Safety Engineer – resulted in approval for the project to proceed without the restriction of enclosing the staircase nor the substantial expense of installing fire sprinklers. The result was a shoe shop with easy access to both sales floors and stockroom, complying with Building Regulations and safe for customers and staff.

This demonstrated the importance of involving a fire safety professional at the early stages of building design.