Firestop Systems: ASTM E814 Test Assembly, Ratings, and Reports

ASTM E814 testing requirements center on building a full-scale firestop assembly, exposing it to a standardized furnace fire under positive pressure, hitting it immediately afterward with a high-pressure hose stream, and recording how long the system blocks flame and heat transmission. The result is a pair of ratings — F for flame, T for temperature rise — tied to the exact tested configuration. Building codes across the United States reference this test when requiring fire protection at penetrations in rated assemblies, which makes it the baseline for virtually every commercial firestop installation in the country.¹

What the Standard Covers

ASTM E814 applies to through-penetration firestop systems installed in openings within fire-resistive walls and floors that are otherwise evaluated under ASTM E119. The standard does not cover membrane penetrations in floor-ceiling or roof-ceiling assemblies tested as part of the assembly under E119, and it does not cover membrane penetrations in load-bearing walls.¹ Those situations follow different code paths, often relying on listed devices like putty pads or steel enclosures.

UL 1479, titled “Fire Tests of Penetration Firestops,” covers essentially the same ground. Building codes and firestop manufacturers routinely reference both as interchangeable, and the International Building Code accepts testing under either one.² If you see a firestop system listed under a UL system number, the underlying test protocol mirrors ASTM E814. The practical difference is that UL also administers its own certification and listing program, so UL system numbers are typically what you look up when verifying that a field installation matches a tested configuration.

Building the Test Assembly

The test starts with a representative assembly that recreates real-world conditions. Lab technicians construct a test frame using common substrates: reinforced concrete slabs, concrete masonry units, or gypsum wallboard assemblies on steel studs. The substrate choice matters because heat transfer characteristics differ significantly between a six-inch concrete slab and a one-hour gypsum wall. A system tested on one may not carry a rating for the other.

Penetrating items go through the barrier next. These include metallic pipes, plastic conduits, insulated pipes, cable bundles, and electrical raceways. The types, diameters, and materials must match what the system is intended to protect in the field. A system tested with four-inch steel pipe does not automatically cover four-inch PVC, because plastic pipe melts away during fire exposure, leaving an open hole the firestop material must seal on its own.

The firestop material — sealant, mortar, wrap strip, pillow, or intumescent collar — is installed around the penetrants following the manufacturer’s exact specifications. Annular space dimensions (the gap between the penetrant and the edge of the opening), sealant depth, and backing material type are all documented precisely. The assembly then goes through a curing period that varies by product chemistry before exposure. Disturbing the assembly during this phase risks compromising the seal and producing an invalid test.

Fire Exposure Procedure

Once cured, the assembly is mounted against a test furnace that follows the ASTM E119 standard time-temperature curve. That curve ramps aggressively: roughly 1,000°F at five minutes, 1,300°F at ten minutes, 1,700°F at one hour, 1,850°F at two hours, and 2,000°F at four hours. The exposure duration depends on the rating being sought, generally one to four hours for commercial applications.

The furnace must maintain a minimum positive pressure of 0.01 inches of water column (about 2.49 Pa) throughout the test.¹ This positive pressure forces hot gases and flames against the firestop, mimicking the stack effect in a real building fire where heated air rises through floor penetrations. Without a pressure requirement, a firestop could pass simply by not being pushed, which would say nothing about how it performs when fire is actively driving combustion products through every available gap.

Thermocouples placed on the unexposed side of the assembly continuously record temperatures at the firestop surface and on the penetrating items. Technicians also watch for visible flames, smoke passage, and structural degradation. These observations feed directly into the F-rating and T-rating determinations.

The Hose Stream Test

Immediately after the furnace cycle, the assembly faces a high-pressure water stream that simulates firefighting conditions. The transition has to happen quickly, and the water must hit the assembly while it is still hot and structurally stressed from the fire exposure.

Water is delivered through a 2.5-inch fire hose fitted with a National Standard Playpipe at a nozzle distance of 20 feet. Nozzle pressure is set at 30 psi for systems seeking a rating of two hours or less, and 45 psi for longer durations.¹ The duration and pattern of water application are calculated based on the assembly’s total exposed area. This phase is where weakened or crumbling firestop material reveals itself. Impact and thermal shock from cold water on a superheated assembly expose any voids, cracks, or delamination the fire created. If water passes through to the unexposed side, the system fails.

F-Ratings and T-Ratings

Every ASTM E814 test produces two separate ratings, and the distinction matters because building codes sometimes require both and sometimes allow only one.¹

The F-rating measures how long the firestop blocks flames from reaching the unexposed side. To earn this rating, the system must prevent any flaming through the assembly during the entire test duration and survive the hose stream test without developing openings that allow water to pass. If flames appear on the unexposed surface at any point, including when a cotton pad held near the seal ignites from escaping hot gases, the F-rating is capped at the time that failure occurred. A system that blocks flame for two hours before the hose stream test, then survives the hose stream, earns a two-hour F-rating.

The T-rating adds a thermal transmission requirement on top of the F-rating criteria. The temperature on the unexposed surface of the penetrant and the firestop material cannot rise more than 325°F above its starting temperature at any monitored point. This threshold exists because even without visible flame, conducted heat can ignite combustible materials on the protected side of the barrier: insulation touching a hot pipe, or wood framing near a steel conduit. If temperatures exceed the 325°F rise at any thermocouple before the full test duration, the T-rating is limited to whatever time elapsed before that failure.

When T-Ratings Are Required

The IBC requires through-penetration firestop systems in fire-resistance-rated floors to carry both an F-rating and a T-rating at least equal to the floor’s required rating.³ The code carves out exceptions for certain floor penetrations, including those contained within a wall cavity above or below the floor, floor and shower drains within a concealed horizontal assembly space, small-diameter conduit into metal-enclosed switchgear, and steel or copper pipes up to six-inch nominal diameter penetrating a single concrete floor. For fire-resistance-rated walls, through-penetrations need an F-rating at least equal to the wall’s required rating but do not need a T-rating.

Related Ratings: L and W

Certain assemblies also need to resist air leakage or water intrusion. These additional performance measures do not come from the base ASTM E814 fire test but are tested under related protocols, often required by the same code sections that mandate F and T ratings.

An L-rating quantifies how much air can leak through a firestop system, measured at a pressure differential of 0.30 inches of water column in both ambient and elevated temperature conditions. The IBC requires L-rated systems wherever penetrations pass through smoke barriers. Leakage through each individual firestop system cannot exceed 5.0 cubic feet per minute per square foot of penetration opening, and the total cumulative leakage for any 100 square feet of wall or floor area cannot exceed 50 cubic feet per minute.³

The W-rating tests whether a firestop system can prevent water from passing through to the other side. This matters in below-grade walls, areas prone to flooding, and any location where water might collect against a fire-rated barrier. The test applies three feet of hydrostatic pressure (about 1.3 psi) against the firestop for 72 hours. Any water passage at all constitutes a failure.² After the water tightness evaluation, the system still has to pass the standard fire and hose stream tests. A system that keeps water out but fails the fire test earns no rating.

What the Test Report Must Document

The ASTM E814 test report is the foundational document that connects a firestop system’s rated performance to its physical configuration. Every listing and certification traces back to this report, so its completeness affects whether the system can be specified and approved for use.

The report includes a detailed description of all materials used in the assembly: product names, physical dimensions, and the specific configuration of each penetrant. It documents the substrate type, the spacing between penetrants, annular space dimensions, sealant depth, and backing material placement. Furnace data logs record temperatures and pressure levels at regular intervals throughout the fire exposure, tracking time-temperature curve compliance and thermocouple readings on the unexposed side.¹

Hose stream test results, visual observations of degradation or flame passage, and the final F-rating and T-rating determinations are all recorded with corresponding time stamps. The report also notes whether the system earned additional ratings like L or W.

The Tested Configuration Governs Field Installations

The ratings apply only to the exact configuration that was tested: the specific substrate, penetrant type, penetrant size, annular space, sealant depth, backing material, and orientation documented in the test report. Change any one of those variables in the field and the rating no longer applies.

Each tested system is published as a listing, commonly a UL system number, that specifies every detail of the assembly. Inspectors verify compliance by comparing the installed condition against the published listing detail for detail. If the listing calls for mineral wool backing at a three-inch depth with one inch of intumescent sealant, installing two inches of sealant with no mineral wool produces an assembly that has never been tested and carries no rating, regardless of whether it seems like it should work.²

Where a listing specifies a dimension as a minimum or maximum, some flexibility exists. Components marked “optional” in the listing can be omitted without voiding the rating. Outside of those explicit allowances, substitutions are not permitted, including substituting one manufacturer’s sealant for another, even if both products individually carry fire ratings.

Engineering Judgments

When field conditions do not match any tested listing and redesigning the construction is not practical, an engineering judgment (EJ) can bridge the gap. An EJ is a professional opinion that a firestop configuration not covered by an existing listing will still perform adequately, based on interpolation or extension of tested systems with similar materials and conditions. The firestop manufacturer’s technical staff typically issues the EJ, sometimes in coordination with a third-party fire protection engineer.²

EJs are not blank checks. They should address minor deviations from tested systems, such as a slightly larger annular space or a different pipe schedule at the same diameter, not untested materials or fundamentally different configurations. The professional issuing the judgment needs to understand the specific site conditions and base the opinion on fire protection engineering principles and direct experience with fire resistance testing. Whether a given code authority accepts an EJ instead of a tested listing is ultimately their call, and some jurisdictions are more receptive than others.

1
ASTM International. ASTM E814 – Standard Test Method for Fire Tests of Penetration Firestop Systems
2
UL Solutions. Firestop and Joint Application Guide
3
International Code Council. IBC Chapter 7 – Fire and Smoke Protection Features