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Leighs Paints are often called by customers to present Continuious Professional Development (CPD) training. The questions below represent some of the most common questions about FIRETEX intumescent coatings asked by delegates:
Is there requirement for both primer and top coat?
Primers form an integral part of the corrosion and fire protection system and we therefore DO recommend the use of a primer. For off-site application is highly recommended as the top coat protects the intumescent coating system during transportation, storage and erection.
Coated steel should not be subjected to standing, ponding or running water and therefore the top coat is important to prevent a breakdown of the fire protection paint if subjected to such. If the site conditions for application are such that the building is fully weathertight and the steelwork will only ever be in a C1 environment then a top coat is not required.
Can you use ANY primer?
No. It is very important to check any primers for generic compatibility as there are even some Leighs primers that are not suitable under FIRETEX. Those that are suitable have been tested/approved for both compatibility as well as fire performance. Primer thickness is also important, dry film thicknesses (DFT) of our primers should not exceed 200 microns unless specifically tested - please consult us if in doubt.
Can you use ANY topcoat?
No. There are 5 topcoats that have been specifically tested/approved for both compatibility and fire performance over FIRETEX coatings. You cannot have any guarantee that the intumescent will not be affected if you overcoat with any other products. Even though other products may be generically similar to our tested products we cannot offer any true assurances. It is also important that re-decoration of topcoats is not carried out indefinitely, too many coats can impair the fire performance.
Is it possible to "top up" a top sealed FIRETEX system with further top coats?
It depends on the top coat used, single pack sheen acrylic finish is fine, two pack polyurethane finish should not be used. This is only available where the original product is the same as the "top up" product, mixing of products is not possible.
Can you fire protect Galvanised Steel?
Yes, but do you really need to galvanise?
We are able to offer an alternative primer only specification. An anti-corrosive primer, when combined with the barrier effect of the fire protection coating, including topcoat will remove the need for galvanising.
FIRETEX can be applied over the galvanising layer of sacrificial zinc. The key issue is to remove any zinc salts BEFORE applying the intumescent with a suitable degreaser, mordant wash and or fresh water. Once all traces of zinc salts have been removed a solvent based intumescent can then be applied, followed by a topcoat. If the FIRETEX product is waterbased then a suitable primer must be applied before application.
Can you fire protect Stainless Steel?
Yes, although we can offer an alternative system with anti-corrosive primer, intumescent and topcoat which will provide corrosion protection for the steel.
FIRETEX can be applied onto stainless steel through the use of a suitable etch primer before the application of the fire protection.
Is there any effect on the DFT of fire protection if a hollow section is filled with concrete?
Yes. We are able to re-calculate the section factor because of the work of Mike Edwards in 1995 later confirmed by Corus as being generic. The section factor becomes Hp/Ae due to the heat sink effects of the concrete core. Therefore the theoretical equations can be presented in this work to calculate the "effective" section factor and design the DFT accordingly.
Is it necessary to fire protect any connection bolts?
Yes, bolt heads and nuts must be protected. Leighs Paints have a
technical bulletin on the subject.
Where "bubbles" have occurred on the underside of the top flange on off-site applied paint (when the shear studs have been fixed) do these need to be removed/repaired?
Providing that these bubbles have not been broken or damaged there is no need to repair or remove them. If they are broken in any way full repair of the coating system IS required. See our technical bulletin for more information.
What are the correct specifications for externally exposed steelwork for various life to first maintenance periods?
For externally exposed steelwork requiring fire protection:
- Using a thin film intumescent and a 150 micron acrylic urethane top coat gives a life to first maintenance is UP TO 10 years
- Using a thick film epoxy product with a 75 micron acrylic urethane top coat, life to first maintenance is UP TO 20 years
For any external specification the top coat is a crucial part of the system and it is therefore advisable to incorporate an inspection regime into the O&M procedure. Any top coat that is seen to have broken down needs to be repaired immediately with any subsequent Intumscent/Primer breakdown also requiring immediate repair
Is there a requirement to mask off contact surfaces where FIRETEX is applied off-site?
This is very much dependent on the paint applicators norms. Most successful applicators do mask off contact surfaces, some using norms as low as 600/700 microns. This process will reduce the need for bolts to be re-tightened once the trapped coating has compressed. HSFG type bolted connections (and their ilk) MUST have contact faying surfaces masked off irrespective of the coating thickness
How soon can fire protected steel applied off-site be moved?
This is very much dependant on the facilities and conditions that the coating is applied in therefore good air movement and temperatures at or above those stated on our data sheets are essential. Thickness applied is also a factor which is very much linked to the required fire resistance period. As a general "rule of thumb":
- 60 minute protection will be ok to handle within 24 hours of application of the intumescent giving a system "cycle" time of 2 days in optimum conditions
- 90 minutes protection will require 2 or more coats and will require at least 48 hours and a cycle of 3-5 days
- 120 minutes protection will require 3 or more coats and will require at least 72 hours and a cycle time of 1-1.5 weeks
The above timings are offered as a GUIDE ONLY in good faith and must not be deemed to offer any kind of assurance or guarantee
How should damaged paint work be touched-up?
The method depends on the level of damage to be repaired. Minor damage can be repaired with a touch-up mastic and the top coat brushed or rollered. More significant levels of damage require the loose materials to be removed back to a firm edge, primer replaced followed by intumescent and top coat. If these areas are quite large and / or a high level of decoration is required then the most appropriate method of application would be by airless spray
Would you like to arrange for Leighs Paints to give a CPD presentation? Perhaps you would like more details on FIRETEX intumescent coatings? The Fire Estimation and Engineering team will be pleased to help, give them a call today on +44 (0) 1204 556423 or alternatively email fireestimation@leighspaints.co.uk.
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