Fire safety
Fire-rated thatch: what Class A actually means.
What the ASTM E108 test measures, what it does not evidence, and how to present it to a Costa Rican plan review, the fire department and your insurer.
Why it comes up
The fire question is what kills most palapa projects.
In hotels, restaurants, condominium amenities and anything subject to fire department review, the thatch idea is usually discarded before it is drawn — for one reason. A vegetal roof is highly combustible and cannot be classified under the roof covering fire test at all.
A roof covering tested Class A changes the nature of that conversation. It stops being an aesthetic preference to be defended and becomes a document that a reviewer, a fire officer or an underwriter can put in a file.
The three classes
What ASTM E108 evaluates.
It is the standard fire test method for roof coverings: it measures how a roof system behaves against fire arriving from outside, exposing the sample to direct flame, burning brands and flying embers of varying size.
- Class A
- The highest severity in the test. It is the classification the NIPA® panel is tested under.
- Class B
- Intermediate severity of external fire exposure.
- Class C
- The lowest severity — the method's minimum threshold.
Three audiences
Who asks, and what each one needs.
The plan reviewer
What belongs in the file is the system's test documentation, not a marketing sheet. It is supplied on request together with the panel data sheet and the warranty letter.
The fire department
Beyond the covering test, review typically covers the roof's relationship to escape routes and to separation between buildings. The test answers for the material; the rest belongs to the project design.
The insurer
Alongside the fire classification come the 260 km/h wind certification and the 6,000 hours of UV exposure. Those three figures are usually what move the premium on a thatch-roofed policy — or make it available at all.
The documentation file
Six documents to have before anyone asks.
All six are issued on request, typically the same business day. Having them early is the difference between a routine review and a stalled one.
- The ASTM E108 Class A test documentation for the roof covering, with its scope stated.
- The wind certification at 260 km/h, and the fixing pattern it corresponds to.
- The ASTM G155 UV exposure report — 6,000 hours — for the durability claim.
- The panel data sheet with dimensions, coverage and installation criteria.
- The warranty letter, stating what is covered, for how long, and by whom.
- Construction details for junctions with hard construction, where fire separation is usually discussed.
Frequently asked
Fire questions in plain terms.
Does Class A mean the roof is fireproof?
No, and it is important not to say that to a reviewer. It means the roof covering was tested at the highest severity level of the external fire exposure test method and performed to that classification. Anything beyond that is overstating the document.
Is this a Costa Rican certification or a foreign one?
ASTM E108 is an international standard test method, which is precisely why it travels: it is recognized by reviewers, fire authorities and insurers who would not accept a manufacturer's own claim.
Do we still need sprinklers or fire separation?
Whatever the building code and the fire authority require for your occupancy — the roof covering classification does not remove any other requirement. It removes the objection to the roof itself.
Can natural thatch be treated to pass?
Fire retardant treatments for vegetal roofs exist, but they degrade with weather and time and have to be reapplied, which makes them very difficult to evidence over the life of a building. That is the practical reason a vegetal roof cannot be classified under this test.
Has someone asked you for the fire documentation?
We send it with the scope of each test stated, the same business day.
