Fire protection of concrete-filled, hollow structural steel
Filling closed profile or structural hollow sections with concrete is a well-known practice in the design of buildings. This method has been used in the construction industry for decades and both circular and square/rectangularprofiles can be treated this way.
Filling hollow sections with concrete offers several advantages over unfilled hollow sections, such as cost versus strength optimisation, durability and aesthetics, increased fire resistance and more.
On occasion, it is necessary to protect these types of sections from fire, in order to meet construction code fire resistance requirements that filling with concrete alone will not meet.
Reactive coatings that are commercially available must be fire tested and assessed to the appropriate test standard that is relevant to the local construction code.
Fire testing of reactive coatings normally encompasses the fire-testing of various sizes of structural steel sections at a number of different thicknesses of protection followed by a statistical analysis, producing interpolations within defined parameters. In Europe these fire tests and assessments for plain structural steel is currently carried out in accordance with EN13381-8:2013. However, there was no standard for testing and assessing concrete filled hollow sections has not been included in this until recently. Prior to having established such testing parameters, how to calculate the amount of intumescent coating for concret- filled hollows was unspecified. This can lead to interpretation and inconsistency in the market and the potential for an uneven competitive landscape. Several academic papers exist and have been used as the basis for guidance. However, suitability of the one size fits all approach is unproven, especially with the market advancing with multiple technologies.
The market position has changed with the publication of EN 13381-6:2012 - “Applied protection to concrete filled hollow steel columns”. This standard has been specifically introduced to allow the testing, and assessment of results, to be done in a consistent manner across all commercially available passive fire protection materials, including reactive coatings available on the fire protection of structural steel market.
Suitable testing and assessment in accordance with this standard is the only way to achieve classification of structural fire resistance in accordance with EN13501-2.
As EN13381-6:2012 is an active standard, it is our recommendation that this should be the sole method of testing and assessment used for concrete-filled hollow steel columns. The use of other mathematical models should be avoided.
More articles
Passive fire protection and the importance of limiting temperature for steel structure
All materials become weaker when they get hot and structural steel is not an exception. Depending on the design of the structure, the steel will have a limiting or critical temperature.
What does this mean, and why is it important? How does it affect the amount of protection needed?
The importance of getting it right
KTA-Tator are a North American company specialising in the testing of steel and concrete structures. With over 70 years' experience they have amassed a sizable body of knowledge, making them one of the leaders in third-party testing in the USA.
One of their consultants, Jay Helsel, recently posted a case study, reporting on the findings of their investigations into the failure of intumescent coatings applied to a project in a north-eastern, coastal location in continental USA.
Passive fire protection of steel structures
A look at the legal or regulatory requirements for passive fire protection of steel structures in Australia, written by John Rakic, Managing Director of Trafalgar Fire.
John discusses the requirements of our own National Construction Code (NCC) encompassing fire testing requirements of AS1530 Part 4 or an equivalent fire test method, along with the strict requirements contained in AS4100 for data analysis and calculation of the thicknesses of fire protection materials required to provide a compliant FRL.
Fire stopping of service penetrations
There are many means through which heat can move from the fire side of a barrier to the non-fire side of a barrier. The fire barrier and/or the fire stopping material(s) themselves can (and do) get hot on the non-fire side in a fire, so choice and construction of fire barriers are important and differ depending on the fire rating duration.
This article assists in making those choices.
product datasheet library
We maintain a library of product datasheets as a ready-reference for you. This library is updated regularly but there are many products available so it isn't possible to provide every datasheet available. We do aim to provide the majority of datasheets for most the popular products.
still can't find what you're looking for?
If you can't find what you're looking for please let us know.
We aim for this website to be a comprehensive source of knowledge for intumescent coatings professionals or anyone with an interest in the subject.
We'll let you know via email when your request has been answered.