7.1 Commentary

This part of BS 5839 is a code of practice providing recommendations, not requirements, for the design, installation, commissioning, and maintenance of fire detection and fire alarm systems. These recommendations reflect recognized good practices and are suitable for most applications.

Key points:

Suitability and Variations: The recommendations may be unsuitable for some applications, leading to unnecessary expense or inadequate protection. Variations may be necessary and must be agreed upon by all interested parties and documented clearly.
Fire Risk Assessment: Variations can result from a fire risk assessment or the engineering judgment of a competent person, considering factors like the extent of protection and system integrity.
Arbitrary Values: Some numerical recommendations are based on custom, practice, or expert judgment and may not need rigid adherence. Examples include maximum zone size, travel distance to manual call points, and sound pressure levels.

In summary, while the standard provides comprehensive guidelines, flexibility is allowed to accommodate specific circumstances and practical considerations.

7.2 Recommendations

a) Clearly identify any variations from BS 5839 recommendations in specifications or design proposals for approval by relevant parties (e.g., user, purchaser, enforcing authority, insurer).

b) Document any variations identified during installation or commissioning that are not in the documented design for subsequent approval (excluding errors or “snags” to be rectified).

NOTE This recommendation is not intended to imply that it is the responsibility of the installer or commissioning engineer to verify or certificate conformity of the system design with this standard. However, if variations are identified by an installer or commissioning engineer, particularly variations related to circumstances that might not have been known to the designer (e.g. structural features of the building that affect detector number or siting, or conditions in the building that might result in an unacceptably high rate of false alarms), they ought to be documented for referral to the designer, user or purchaser for agreement or action.

c) All variations, whether of the type described in a) or b), should be agreed amongst the interested

parties (see Clause 6).

d) All variations should be listed in the relevant system certificate (see Clause 41).

e) Major non-compliance (see 46.2) that are agreed variations should be clearly recorded in the logbook so that they are readily available for future reference by maintenance companies and any other interested parties.

7 Variations from the recommendations of this standard