Frequently asked questions
Answers to your cast-in fire collar questions
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Specifier essentials
Sure Snap cast-in fire collar FAQs
Fast to fit. Certified to perform. Simple to specify.
Straight, specifier-grade answers on what decides a compliant seal: pipe and fitting compatibility, slab depth and annular gap, fire ratings, and fast on-site installation. Every answer draws on Sure Snap’s LPCB-certified test data.
Product and specification
What a cast-in collar is, the pipes and slab depths it suits, and the figures you need to specify it.
A cast-in collar is designed into the slab before the concrete is poured. It is fixed to the formwork by its locator plate and cast in place, so the firestop is integral to the structure. A retrofit (wrap) collar is fitted around the pipe after the slab is built. Sure Snap is a cast-in system, which means the seal is planned and installed as each floor is poured rather than added afterwards.
In normal use the collar sits cast into the slab around the pipe. In a fire, the nylon fuse-links holding the springs melt, and the loaded springs compress the Intumesh™ intumescent around the softening pipe. As the pipe collapses, the intumescent swells to fill the opening and seals the penetration, maintaining the slab’s fire resistance for up to 4 hours depending on the pipe and configuration. The patented spring activation is what lets it close fast, in around three minutes.
Sure Snap collars are tested with a wide range of plastic pipes, including U-PVC, P-PVC, C-PVC, HDPE, MDPE, ABS, PP-R and PE-X, plus certain named systems and fittings. The three collar sizes cover nominal pipe diameters up to about 63 mm (H65S), 110 mm (H110S) and 160 mm (H150S). The exact diameter range that is covered depends on the pipe type, so always check the fire rating by pipe table before you specify.
Sure Snap provides up to 4 hours’ fire integrity (E 240), with insulation up to 3 hours (EI 180), depending on the pipe type, pipe diameter and collar size. Performance is set by the Extended Application Report, so the rating for your specific configuration comes from the fire rating tables, not a single headline figure. Sure Snap is tested as a smoke and fire seal, which matters because much of the risk in a building fire comes from smoke spreading between compartments.
Sure Snap is tested in concrete slabs from a minimum thickness of 150 mm and a minimum concrete strength of 20 MPa. The collar must sit flush with the underside of the slab and cannot be recessed. Thicker or denser slabs are permitted; thinner or weaker slabs are outside the tested scope.
The standard collar height is 250 mm. For slabs deeper than 250 mm, add stackable extensions in 50 mm increments. For shallower slabs, Selkent offers bespoke collar heights to suit your slab depth. Any trimming on site must follow the installation instructions; do not otherwise cut or modify the collar.
The Manifold Recess Former (MRF) is an accessory for the H110S collar. It recesses the collar up into the slab so a pipe manifold can sit above it, which reduces the pipework head height below the floor. Use it where a manifold connects several pipes close to the slab.
Certification and compliance
The third party approvals behind Sure Snap and how to specify it on a compliant basis.
Yes. Sure Snap holds LPCB Certificate of Product Approval No. 1833a and is listed in the LPCB Red Book. The collars were tested by BRE Global at Watford (a UKAS-accredited laboratory) to BS EN 1366-3 and classified to BS EN 13501-2, with extended application to BS EN 15882-3, documented in Extended Application Report P104650-1003 Issue 3.
Yes. The H65S, H110S and H150S collars are listed on NBS Source, so you can pull Sure Snap straight into an NBS specification.
No. You can only use the collar in applications that have been tested or included in the Extended Application Report at the given fire rating level. When assessing the collar, consider the pipe type, pipe size and slab thickness together. Refer to the collar product pages and approval charts for the full list of fire-rated system configurations.
Installation
Fitting the collar correctly on site, from annular-gap sealing to what you must not do.
Sure Snap collars have been tested with fittings pushed up inside the collar for a number of pipe types and diameters. Check the fire rating tables to confirm that the measured pipe wall thickness allows a fitting. Some pipe types are difficult to close, so fittings in those pipes are not covered by testing or assessment.
Yes. For pipes that run close together, Connection Clips join adjacent H110S collars neatly for cluster installs. Check the spacing and configuration against the installation instructions and the fire rating tables for the pipe types involved.
The requirement depends on the size of the annular gap on top of the slab.
| Annular gap | Sealing requirement |
|---|---|
| Up to 10 mm | No backfill required. |
| 10 mm to 20 mm | Sika Everbuild Everflex LMA 200 Contractors Sealant, applied between the pipe and the aperture in the floor to a depth of 10 mm. |
| 20 mm to 40 mm | A non shrink general purpose grout (Weber Saint Gobain). A cardboard gasket is positioned either 30 mm below the upper surface of the floor, or on the rubber ring of the collar if that is less than 30 mm below the surface, and the grout is applied in the gap above it. |
For polypropylene (PP) pipes, an additional PE foam strip is also required (see the polypropylene pipes question below).
No. Fire foam is not to be used in any situation.
No. There should never be any concrete in the spring pockets. Concrete that leaks in during installation can stop the collar activating in a fire, which leaves it non-compliant. The locator plate is designed to block slurry and help keep the pockets clear during the pour.
Yes. For PP pipes, fit a PE foam strip (around 5 mm by 30 mm) around the pipe, flush with the top of the slab, in addition to the standard annular-gap sealing. Follow the Sure Snap installation instructions (INS-HT-SS-V2) for the detail.
No. The collar cannot be altered in any way other than as prescribed by the installation instructions. If you need a non-standard height to suit your slab, use Selkent’s bespoke collar heights or stackable extensions rather than modifying the collar on site.
Ordering and support
Where to buy Sure Snap in the UK, on-site training, and where to find the technical downloads.
The fuse-link is the nylon link holding the spring ends together. If it breaks before the pipe has been installed, replace the fire collar or fit a new fuse-link on the activated spring, and contact the distributor for a replacement. If it breaks after the pipe has been installed, the fire collar is still compliant and no further action is needed.
Sure Snap is supplied and supported in the UK by Selkent, the sole UK distributor. Selkent holds stock, handles bespoke height orders, and provides technical and specification support. Call 020 8699 6777 or email sales@selkent.com.
Yes. Selkent offers free on-site toolbox talks delivered by its technical sales team, so your installers can learn the correct cast-in method before the pour. Get in touch to arrange one.
Datasheets, installation guides, fire rating tables, certification and CAD/Revit files are all available to download. Use the drawings page for DWG, PDF and Revit/BIM models, and the compliance section for the fire rating tables and certificates.