The BSI Kitemark on Flexigas is not a one-off self-declaration. It is independent, ongoing third-party certification by BSI, backed by regular factory audit and product testing, so the licence has to be earned and kept. Flexigas holds Kitemark KM 598726 against scheme BS EN 15266:2007, with maximum operating pressure 0.5 bar. The scheme also references PP1634 for the special adapter fittings and PP1691 for the integrated earth terminals, both dated July 2021. The licence currently runs to 11 July 2027. Two rules keep the Kitemark valid on your install: Flexigas tubing and fittings only ever go together (mixing in another manufacturer's CSST voids both the Kitemark and the warranty), and any connection to copper, iron or brass is made through approved BSP thread connectors. The FG Link adapters carry extra conditions: the installer must have completed Flexigas training, and the adapters may only be combined with fittings on the Flowflex Compatible Model List (Rev 1, 19 July 2021). For building control, the certificate is your evidence. Download it at /technical-downloads/.
A plain reference for Gas Safe registered engineers on what the Flexigas Kitemark actually is, exactly what KM 598726 covers, the rules that keep it valid on your job, and what to hand building control. No marketing copy. Just the certification facts and where to get the paperwork.
1. What a BSI Kitemark actually is
A lot of products carry a logo that looks like a mark of quality but is, underneath, the manufacturer's own word. The BSI Kitemark is not that. It is one of the oldest and most recognised product certification marks in the UK, and it means three specific things.
- Independent. The certification is granted by BSI (the British Standards Institution), a third party, not by the manufacturer. Flexigas does not award itself the mark.
- Ongoing. A Kitemark is not earned once and kept forever. BSI carries out regular audits of the factory and the quality management system, plus periodic testing of product pulled from production, to confirm the product still meets the standard. If it stops meeting the standard, the licence can be suspended or withdrawn.
- Tested to a published standard. The mark is always tied to a specific British or European standard, so you can see exactly what was tested and to what specification.
In short: a Kitemark tells you an independent body has tested the product against a named standard and keeps checking that it still passes. That is a meaningfully different thing from a self-declared CE-style statement or an in-house "tested to" claim.
Flexigas is not the only CSST product to hold a Kitemark, and we do not claim it is. Several CSST brands hold Kitemarks. The point here is what our licence covers and how to keep it valid on your installation.
2. The scope of KM 598726
The Flexigas Kitemark licence number is KM 598726. Here is what sits inside it.
| Item | Detail |
|---|---|
| Kitemark licence number | KM 598726 |
| Certification scheme (standard) | BS EN 15266:2007 (stainless steel pliable corrugated tubing kits for gas, up to 0.5 bar) |
| Maximum operating pressure (MOP) | 0.5 bar |
| Special adapter fittings reference | PP1634 (July 2021) |
| Integrated earth terminals reference | PP1691 (July 2021) |
| Licence expiry | 11 July 2027 |
A few notes on each line.
The standard: BS EN 15266:2007
This is the European standard for pliable corrugated stainless steel tubing kits used to carry gas at pressures up to 0.5 bar. It is the same standard referenced throughout the Flexigas Installation Manual. When building control or a specifier asks "what is it certified to", BS EN 15266:2007 is the answer.
The pressure: MOP 0.5 bar
Maximum operating pressure for Flexigas is 0.5 bar. That figure comes straight from the scheme standard and covers first, second and third family gases. Do not quote a higher figure. Domestic natural gas runs well inside this (meter pressure 21mbar per BS 6891), so 0.5 bar is the ceiling, not the working pressure.
The two scheme references: PP1634 and PP1691
The Kitemark scheme references two additional product specifications, both dated July 2021:
- PP1634 covers the special adapter fittings (the FG Link / A-XX adapters that let Flexigas transition to other systems). This is why those adapters carry their own conditions, set out in Section 4 below.
- PP1691 covers the integrated earth terminals (the FG Bond bonding terminal built into the fitting). It is the reason the integrated terminal can be relied on for equipotential bonding rather than being treated as an extra.
The expiry: 11 July 2027
The current licence runs to 11 July 2027. Because a Kitemark is renewed on the back of continued audit and testing, this date is the live licence period, not the manufacture date of any one coil. If you ever need to confirm the certificate is current for a particular job, the in-date certificate at /technical-downloads/ is the document to check.
3. The two rules that keep the Kitemark valid on your install
The Kitemark covers Flexigas as a system: the tubing and the fittings tested together as a kit. Two rules follow directly from that, and breaking either one takes your specific installation outside the certified system.
Rule 1: Flexigas tubing and Flexigas fittings only, never mixed with another CSST brand
Flexigas tubing is only compatible with Flexigas fittings. Mixing Flexigas tubing or fittings with another manufacturer's CSST voids the Kitemark and the warranty. It does not matter how similar another brand's tube or fitting looks. The systems are tested as kits, not as interchangeable parts, and they are not certified to work together. Section 24 of the Installation Manual is unambiguous: no Flexigas component should ever be connected directly with any other CSST system.
Rule 2: connect to other piping systems only through approved BSP thread connectors
You can and routinely will join Flexigas to copper, iron and brass. That connection is made only by means of approved BSP thread connectors. Direct joining to another CSST system is forbidden; transitioning to a different type of pipe (copper, iron, brass) through a proper BSP threaded connection is exactly how the system is designed to interface with the rest of the installation.
Get these two right and your install stays inside the certified Flexigas system. Get either wrong and you have, in effect, built something the Kitemark was never granted against.
4. The FG Link and adapter conditions
The special adapter fittings (FG Link, the A-15 through A-40 adapters covered by PP1634) let Flexigas transition to a FlowFlex system. They carry two hard conditions written into the Kitemark scheme. Miss either and you take the adapter outside its certified use.
- Training. Adapter fittings may only be assembled by stockists and installers who have completed a Flexigas training course on adapter assembly. This is not a general competence assumption; it is a specific condition of the certification.
- The compatibility list. Adapter fittings may only be combined with fittings on the Flowflex Compatible Model List, Rev 1, dated 19 July 2021. If a fitting is not on that list, it is not a certified combination.
If you have not done the adapter training, or you are not working from the current Flowflex Compatible Model List, do not use the adapters. Talk to Flexigas technical and we will sort the training and the list.
5. What to show building control
When building control, a specifier or a clerk of works asks you to evidence the product, you do not need to argue the case. You hand over documents.
- The BSI Kitemark certificate for KM 598726. This is the headline evidence: it names the licence number, the standard (BS EN 15266:2007), the scope and the licence period. It is the single document that proves the product is independently certified and currently in licence. Download it at /technical-downloads/.
- The Flexigas Installation Manual. Evidence that the install was carried out to a documented method built on BS 6891:2015 (DN15 to DN32) and IGEM/UP/2 (DN40 and DN50). Available at /technical-downloads/.
- Your Gas Safe registration and ACS. All gas work in the UK must be carried out by a Gas Safe registered business or self-employed person holding valid ACS (or allied NVQ/SVQ), in accordance with the Gas Safety (Installation and Use) Regulations 1998. That is the competence side of compliance; the Kitemark is the product side.
For an installation that uses the adapters, also keep a record that the assembling installer holds the Flexigas adapter training, and that the fittings used are on the Flowflex Compatible Model List (Rev 1, 19 July 2021). That closes the loop on the PP1634 conditions if anyone asks.
The short version: certificate proves the product, manual proves the method, Gas Safe proves the engineer. Together they answer almost any compliance question on a domestic or light-commercial Flexigas job.
6. Why this matters commercially, not just on paper
The Kitemark is not box-ticking. On a spec-led or insured job, an independently certified product is the difference between a clean sign-off and a query that holds up the next stage. It is also what stands behind the warranty: install inside the certified system, with Flexigas tubing and Flexigas fittings and proper BSP transitions, and the 25-year warranty and the certification both hold. Step outside it (a foreign CSST fitting, an untrained adapter assembly, an off-list combination) and you have, on paper, voided both at once. Keeping the install inside KM 598726 is the cheapest insurance on the job.