Passive fire protection of steel structures

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Structural steel, by definition, is a steel structure that is helping to hold up a building.

The steel structure might consist of vertical columns and horizontal beams, along with some bracing. The beams might be supporting a composite concrete slab. 

In a building fire, temperatures can quickly rise within a compartment space to 500˚ C and, without sprinkler intervention, the temperature can continue to rise significantly, as long of course as there remains sufficient fuel and oxygen to allow sustained combustion. 

Without adequate passive fire protection applied to these steel structures, at these elevated temperatures the steel loses strength and starts to bend and, in extreme cases, can result in the collapse of part of or all the building. 

Twisted steel after a fire

Passive fire protection isn’t hard to understand. You apply material over the steel, to provide insulation to keep the steel below the temperature where it can start to lose strength. 

Whilst the concept is simple, the application is far from that and requires considerable experience and a comprehensive understanding of the subject.

The attached article delves much more deeply into the matter, providing a valuable insisght into the intricacies and requirements of passive fire protection of steel.

Below are some dot-point conclusions but we recommend that you download and read the full article. 

  • NCC requires strict use of AS4100 and 7 coefficient linear regression for determination of FRLs
  • Fire testing must include full scale load bearing elements 
  • All fire test assessment reports must include the seven coefficients, k0, k1…k7 
  • Don’t be fooled by the big name suppliers; ask for their fire test assessment report and double-check compliance yourself 
  • The fire test assessment report should be readily available on the product supplier's website
  • Fire test laboratories are culpable in part for some confusion in the market by way of writing assessments that do not include the NCC requirements for AS4100 and the seven coefficient linear regression analyses mandatory requirement 
  • If it says in the assessment report it may, instead of it does, be concerned as you might not be installing compliant steel passive protection systems under the so-called "Deemed to Satisfy Provisions" 
  • If in doubt ask... the staff at Trafalgar are happy to review reports and point you in the right direction 
  • You can trust Trafalgar; we believe safety should never be taken for granted 
Passive fire protection
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