Hostel conversion and the single-stair argument
Your client owns an eight-storey 1970s office block in Nairobi with a floor plate of 780 m2, a single 1.2 m wide staircase, 2.7 m ceiling heights and no sprinkler system. The client wants to convert it into a 220-bed student hostel and has been told by a county officer that, because the structure is existing, only 'minor renovation' approval is needed. Your preliminary review shows a 34 m travel distance from the farthest bed to the single stair, a 1.5 m corridor, a dry riser, and a 300 m2 basement proposed for storage. The client wants to start internal demolition in four weeks and has asked you to sign the county application as 'minor renovation' so that the project is not delayed. The building will remain occupied in phases during construction.
1. Identify the fire-safety issues that determine whether the conversion can be approved, and explain why the 'existing building' argument is not decisive.
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The determinative issue is the change of use and the resulting change in occupancy risk, not the age of the structure. An office population is awake, mobile and familiar with the building; 220 sleeping students are not. That change affects exit provision, travel distance, compartmentation, detection and evacuation strategy.
On the facts: a single 1.2 m stair serving eight storeys and 220 beds is the critical defect. A second, protected stair or an equivalent smoke-protected escape route is likely to be required. The 34 m travel distance from the farthest bed exceeds the normal unsprinklered benchmark for a sleeping risk and cannot be cured by a dry riser alone. The 1.5 m corridor may be adequate for the occupants of one floor but becomes a bottleneck where it feeds the single stair. The 300 m2 basement storage needs separation from the accommodation and its own escape and smoke control. The absence of sprinklers and automatic detection increases the required standard of passive protection.
The 'existing building' argument is not decisive because grandfathering generally protects continued use, not intensification or a change to a more hazardous use. A material alteration or change of use triggers an upgrade of the life-safety provisions. The county officer's label of 'minor renovation' does not override the applicable code or the professional duty to certify accurately. The correct starting point is a fire-engineering assessment of the proposed use, not a renovation label.
2. Set out a compliance strategy and approval sequence you would recommend, including what you would refuse to do.
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I would recommend a two-track strategy: establish the minimum acceptable life-safety package, then negotiate a phased implementation that keeps the building usable during construction.
First, appoint a fire engineer and carry out a fire strategy for the hostel use. The strategy should test occupancy load, exit capacity, travel distance, compartmentation, smoke control, detection, sprinkler protection, basement separation and the evacuation of sleeping occupants. Second, hold a pre-application meeting with the county fire and building-control officers to agree the design basis before submitting drawings. Third, submit a full change-of-use application supported by the fire strategy, structural appraisal and phased-works method statement. Fourth, sequence the works so that the new escape stair, compartmentation and detection are completed before any floor is occupied as a hostel.
I would not sign the application as 'minor renovation'. That would misrepresent the nature of the works and could expose the client and me to enforcement action and liability. I would also refuse to certify occupation of any floor until its escape route, detection and fire separation are complete and tested. If the client rejects the upgrade, I would put my advice in writing and decline to act as certifying architect for the conversion. The professional obligation is to record the risk, not to manufacture a compliant paper trail.
3. The client proposes to keep the single stair but add sprinklers and a fire alarm. Assess that proposal.
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Sprinklers and detection improve the probability of early control and warning, but they do not automatically cure a single-stair deficiency in an eight-storey sleeping building. The stair is the last line of escape if the alarm is delayed, if the fire starts in the stair or if smoke enters it. A single unprotected stair also creates a serious problem for firefighting and for phased evacuation.
The proposal should therefore be tested, not accepted on assertion. The fire engineer should show how the added systems achieve an equivalent level of safety: full sprinkler protection, automatic detection throughout, a smoke-protected stair lobby, fire-resisting construction around the stair, protected escape from the basement, and a credible evacuation plan for 220 beds. Even then, many authorities will not accept a single stair for this height and occupancy because the consequence of failure is catastrophic.
My advice would be that sprinklers and alarm are necessary but probably not sufficient. The client should cost a second protected stair early, because discovering the requirement after demolition will be far more expensive. If the client insists on a performance-based single-stair case, it must be independently peer-reviewed and accepted by the authority before construction, not presented as a minor variation.