Crib 5 vs Source 0 and 1: Which Fire Test Does Your Restaurant Seating Need?

Source 0 is a smouldering cigarette and Source 1 a match-sized gas flame; together they make up the BS 7176 low hazard level. The Crib 5 fire test adds a small burning wooden crib and is part of the medium hazard level that the standard’s guidance gives for restaurants, pubs and hotel bedrooms. Most UK hospitality seating needs all three.

Fire specifications for hospitality seating tend to collapse into shorthand: “Source 0/1”, “Crib 5”, “BS 5852”. The terms are not interchangeable, and choosing the wrong one can mean re-covering a dining room before opening night. This guide compares the tests, explains what each one simulates and how it is run, shows which level typical UK venues ask for, and lists the specification mistakes we see most often, so that your restaurant chairs and banquettes are specified correctly from the first quotation.

What are Source 0, Source 1 and Crib 5?

They are three of the ignition sources defined in BS 5852:2006, the British method for assessing how easily upholstered seating ignites. Source 0 is a smouldering cigarette. Sources 1 to 7 are flaming sources made from butane gas flames and wooden cribs, ranging from a match-sized flame up to roughly the burning of four double sheets of full-size newspaper (NSAI listing of BS 5852:2006). Source 1 is the match-sized flame; source 5 is the smaller of the two wooden cribs that contract specifications usually call up, and source 7 the larger.

BS 7176, the specification for non-domestic seating, refers to BS 5852 and to the European methods BS EN 1021-1 (cigarette) and BS EN 1021-2 (match-flame equivalent) (BSI). For the low hazard level it uses the two EN 1021 tests, which is why “Source 0 and 1” and “EN 1021-1 and -2” tend to be used as the same thing on spec sheets.

Crib 5 fire test vs Source 0 and 1: how do they compare?

The difference is the size and type of the ignition source. Sources 0 and 1 represent everyday accidents: a dropped cigarette or a lit match. The crib is a far larger flaming source placed on the seat, so a composite that passes the first two can still fail Crib 5.

Cigarette and match criteria are from RISE’s description of EN 1021 testing (RISE); crib descriptions are from SATRA (SATRA).

Which test does your restaurant seating need?

For most restaurants, pubs, bars and hotel bedrooms the answer is Crib 5 plus Sources 0 and 1. BS 7176’s guidance table, as summarised by SATRA, places those premises in the medium hazard category, which requires the low hazard cigarette and match tests plus ignition source 5 on the cover and filling composite. Offices, schools, colleges and museums appear under low hazard, where Source 0 and 1 alone apply.

When Source 0 and 1 alone might be accepted

A staff room or a meeting room in an office building could fall under low hazard. Do not assume it from the room’s name on a plan; the category depends on how the space is used and on the fire risk assessment, so ask the assessor to confirm it in writing.

When to go beyond Crib 5

High hazard, which calls for Crib 7, is listed for sleeping accommodation in certain hospital wards and hostels and for offshore installations. A hospitality operator is unlikely to need it for a dining room, but serviced accommodation with vulnerable residents, or a venue where the assessor has concerns about deliberate fire-setting, may be assessed differently. See our BS 7176 guide for all four categories.

How is the Crib 5 test run, and what does a pass look like?

The laboratory builds a mock-up from the actual cover, any interliner and the actual filling, places the lit crib on it and observes whether flaming and smouldering stop. A published certificate from West Yorkshire Joint Services, for a contract fabric tested to BS 5852:2006 clause 11 over 35 kg/m³ combustion-modified high-resilience (CMHR) foam, shows the wording to look for: flaming ceased within the specified ten-minute period after ignition of the crib, and there was no progressive smouldering. The same certificate states that it relates only to the sample received (test certificate).

That last sentence is the one most often overlooked. A fabric with a Crib 5 pass over 35 kg/m³ CMHR foam says nothing about the same fabric over a different foam, without an interliner, or with a fibre wrap added for comfort. When you read a certificate, check four things:

• The standard, clause and ignition source (for example BS 5852:2006, clause 11, source 5).
• The exact filling, including type and density, and any interliner.
• Whether the cover was water-soaked first, which matters for treated or back-coated fabrics.
• The laboratory, the date and the fabric reference, matching what you are buying.

Why the domestic regulations also mention Crib 5

The Crib 5 name appears in the domestic rules too, which causes confusion. Schedule 1 of the Furniture and Furnishings (Fire) (Safety) Regulations 1988 tests polyurethane foam under a standard 100% flame-retardant polyester cover with an “ignition source 5 crib”; the result is judged against flaming and smouldering criteria and, in some cases, a mass loss of less than 60 g (legislation.gov.uk). That is a test of the filling with a reference cover, not of your chosen fabric over your chosen foam.

So a domestic compliance label is not evidence that the composite passes Crib 5 in the way BS 7176 medium hazard requires. For contract seating, ask for the composite result.

What specification mistakes cause problems?

• Writing “BS 5852” with no ignition source. The standard covers sources 0 to 7, so the line is meaningless without “source 5” or a hazard category.
• Accepting a fabric-only certificate. If the test foam differs from the production foam, the evidence does not apply.
• Late fabric changes. Switching to a customer’s own fabric after sampling restarts the compliance question.
• Forgetting secondary upholstery. Booth back cushions, seat pads on timber chairs and scatter cushions are composites as well.
• Ignoring cleaning. Treated covers need water-soak evidence, and the cleaning regime should match the fabric’s cleaning code.

For booths and banquettes in particular, ask for the fire build per component; our booth and banquette seating is quoted that way. The choice of fabric route also affects the result, which we cover in our guide to fire-retardant upholstery fabric.

Frequently asked questions

Sources

1. BS 5852:2006 Methods of test for assessment of the ignitability of upholstered seating by smouldering and flaming ignition sources, NSAI Standards Store (BSI standard listing) (accessed 28 October 2026)
2. Upholstered contract furniture flammability, SATRA Technology (accessed 28 October 2026)
3. EN 1021: fire testing of upholstered furniture, RISE Research Institutes of Sweden (accessed 28 October 2026)
4. The Furniture and Furnishings (Fire) (Safety) Regulations 1988, Schedule 1, legislation.gov.uk (accessed 28 October 2026)
5. BS 5852:2006 Clause 11, Source 5 test certificate (Morph fabric over 35 kg/m3 CMHR foam), West Yorkshire Joint Services Materials Testing, published by Gabriel (accessed 28 October 2026)
6. BS 7176:2007+A1:2011 Specification for resistance to ignition of upholstered furniture for non-domestic seating by testing composites, BSI Knowledge (accessed 28 October 2026)