When a buyer sends a fire spec for auditorium seating, the first thing we do is check whether it is still current. More than half the briefs we get name a standard that changed years ago, and building to a repealed test is a quiet way to fail the real one. So before any tooling, we confirm the exact requirement the local authority enforces.
What TB 133 was, and why people still ask for it
California Technical Bulletin 133 was, for years, the benchmark for upholstered seating in public occupancies — auditoriums, stadiums, nursing homes, jails, day-care centres — defined as any area with ten or more pieces of seating. It was a full-scale test: a finished chair or mock-up is put in a sealed room and hit with an open flame of about 16 kW for 80 seconds, while the rig logs heat release, mass loss and carbon-monoxide levels. It is a tough, expensive test because it burns a real seat, not a fabric swatch.
The catch: TB 133 was repealed effective 22 January 2019. California folded its requirements into the smoulder-based TB 117-2013, which the federal government adopted nationally under 16 CFR 1640. So a buyer who specifies "must pass TB 133" today is usually working from an old document. We will build to it if a specific venue still contractually demands it, but we tell you it is no longer the default — TB 117-2013 is.
EN 1021: a different philosophy
Europe approaches the same risk from the component side. EN 1021-1 tests resistance to a smouldering cigarette; EN 1021-2 tests a small match-equivalent flame. Both are applied to the upholstery-and-filling combination, not to a whole burning chair. That makes them cheaper and faster to run, but it also means passing EN 1021 is not the same evidence as passing a full-scale TB 133 burn. They answer different questions: "will a dropped cigarette start a fire?" versus "how does the whole seat behave once it is alight?"
The trade-off we put to buyers
Fire performance is bought in the foam and the cover, and that is where price-driven suppliers cut. A fire-retardant foam grade and a tested fabric cost more per seat than a standard cushion — sometimes meaningfully more across a 500-seat hall. The temptation is to quote standard foam and "confirm fire rating later." We refuse that, because later is after tooling, and a foam change at that point is a re-spec, not a swap. The honest version is: tell us the venue's enforced standard up front, we quote the right foam from seat one, and the price reflects reality instead of surprising you at the fire report.
Why the test method changes the whole seat
A full-scale burn test and a component smoulder test pull the design in different directions, and that is worth understanding before you pick a foam. A full-scale standard rewards a seat that resists sustained burning as an assembly — the cover, the foam, the interliner and even the way they are stitched all matter, because the test sets a real seat alight and watches the system. A component test like EN 1021 mostly rewards the right combustion-modified foam and a cover that does not ignite from a small flame. So a seat tuned to pass one is not automatically the cheapest way to pass the other. We have seen buyers specify an expensive fire barrier cloth they did not need for a smoulder standard, and others skip the interliner that a full-scale burn required. Telling us the exact test up front lets us spend the fire budget where that test actually looks.
What we will not do is print "fire certified" on a product. We build to fire-retardant foam grades and the named test method, and third-party fire and load testing can be arranged per order and per market. The certificate belongs to your specific build, tested — not to a brochure.
The structural durability that sits underneath all this is a separate question — covered in our EN 12727 levels note — and the two are quoted together on a fixed-seating order.
If you have a hall or multiplex coming up, send the local fire standard and a rough seat count and we will quote the foam and cover that actually clear it. The structural side is covered in our EN 12727 durability note; reach the desk via our contact form.