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21 March 2019

Balancing Fire Protection with Other Building Requirements


While on a renovation construction site recently, we were looking at challenges faced by the main contractor regarding fire stopping of existing service penetrations. The building is a heritage site, adding to the complexity of the challenges.

There were, as you could imagine, all manner of features of the original architecture and structural integrity that were to remain undisturbed — as per the building consent.

The fire engineers were particularly sensitive to the requirement to increase the fire resistance rating of certain walls. These walls could not be replaced. Structural engineers were likewise extremely cautious about the seismic strength limitations of the original structure, and some of the reinforcements were quite ingenious.

In these types of projects, there is always going to be some conflict in the application of the various standards of the NZ Building Code.

Seismic vs fire — which standard to comply with?

We often come across situations where compliance with the building code requirements for fire protection is in conflict with the requirements for seismic protection.

There have been instances where a sprinkler pipe (for example) needs to be retrofitted through a load bearing wall and the requirement is for the penetration seal to have sufficient flexibility to accommodate seismic movement. It is then established that this same wall is a firewall and all penetrations should be stopped to the same fire resistance rating as the wall. This, in general, necessitates a fixed seal to prevent the spread of smoke and fire.

Herein lies the conflict.

In this particular case, our attention was drawn to a particular retrospective application of the Boss FyreBox in a building in Wellington during earthquake strengthening remedial work. The fire and structural engineers got together and, together with the Manufacturers Declaration of Support, were successful in getting the local authority to accept their alternative design. The Boss FyreBox is compliant for new and retro installations in numerous substrates on a variety of mixed services.

In the case of the Boss FyreBox being used to seal a 50mm galvanised steel pipe for up to 120 minutes (FRR-/120/60) AND achieve a flexible seismic service penetration, we need not look further than recent fire test assessments for evidence of compliance.

Fire protection for vegetation roots

Yes we are serious! We were taken to see a root of a huge vine protruding through a “heritage building wall” into the building. The main contractor had been told by the local authority inspectorate, they were not allowed to “trim or damage” this main root (without incurring a substantial fine) in their attempts to fire protect the wall.

This protected species of plant appears, on face value, to have precedence over human life.

As they were aware there would be no fire testing done on mature vegetation, the contractor wanted to know if the principles would be the same. They wanted to know whether all they needed to do was propose the fitting of a right size fire collar around the root to the fire engineer and local authority, and state it was an ANARP solution (As Near As Reasonably Practicable solution).

After we regained our composure and realised this was in fact not a hoax, some serious questions came to mind. None of which had answers.

Our proposed solution has been put to the local authority for acceptance/approval prior to any installation work commencing. The fire engineer is relieved that there is a practicable solution.

Passive fire protection industry finding its feet

These incidents are more commonplace than we ever anticipated — not the application to mature vegetation, but the continued dismissive approach taken by those with little if any knowledge of the industry.

The industry is fast developing an identity of its own and ethical participants will be rewarded. The installation companies with documented quality control processes to ensure the designs and specifications are not only fit-for-purpose but fully compliant before and after installation is undertaken are the ones to be taken seriously. Their quality assurance systems should provide documentary evidence of correct and compliant installation to back-up their QC processes.

This QC and QA documentation should form part of the initial screening performed by the contractor before asking for a price to do the work — passive fire protection is not a race to the bottom of the cliff based on price.

If they are flying by the seat of their pants, as it were, it is likely you would find a pipe collar around the vine root in the cellar of the heritage building — signed off by your local authority.

It may take a little time to verify or consult on a proposed solution and, if we as an industry are to take our “duty of care” responsibilities seriously, we owe it to ourselves and to our community to perform at least a basic due diligence to avoid doing jail time. Don’t let your sub-contractor get it wrong. The cost of reworks and rectifications come directly off your bottom line.

View more information on Potter Interior Systems, including contact details.
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