SettingsSettings for this calculationUS
The combined perimeter length of all penetration openings being firestopped.
Sum the perimeter of every pipe, conduit, or cable penetration in the assembly — e.g. π × diameter for each round penetration.
The width of the gap between the penetrating item and the edge of the opening.
This is the space the firestop sealant must fill around the penetrating pipe, conduit, or cable bundle.
The thickness of sealant the tested system calls for at each treated face — not the thickness of the wall or floor.
Read this off the UL or EN listing for the system you are installing, where it appears as the fill or caulk depth: commonly 12-25 mm (1/2-1 in) per face, sometimes 50 mm. The rest of the annulus is packed with mineral wool or a listed backing, which is a separate material line and is not sealant. Where a system is sealed on BOTH faces, total the two depths here. Entering the assembly thickness instead will over-order the sealant several times over.
Firestop caulk needed
0.993 gal
Always use a firestop sealant system that is UL-listed for your specific penetration type (cable, pipe, conduit) and the fire-rated assembly being penetrated — this calculator estimates volume only, it does not verify UL system compliance.
They open the calculator with your figures already in it
Penetration Firestop Caulk Volume Calculator: 0.9927 gal — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- Firestop sealant volume = total penetration perimeter × annular gap width × firestop depth, the standard method for estimating a continuous sealant bead around penetration openings
Inputs used
- Total Penetration Perimeter (Sum of All Openings)
- 49 ft
- Annular Gap Width
- 0.39 in
- Sealant Fill Depth (From the Listed System)
- 1 in
Confidence note: Always use a firestop sealant system that is UL-listed for your specific penetration type (cable, pipe, conduit) and the fire-rated assembly being penetrated — this calculator estimates volume only, it does not verify UL system compliance.
What this calculation does not cover
- The listing sets a minimum and a maximum annular space, and a gap outside that range has no system at all. Cored holes come out oversize and pipes never sit centred, so it is the widest point of the real gap that has to be checked against the listing — where it is too wide the answer is to reduce the opening, not to pump in more sealant.
- The perimeter-times-gap model falls apart on cable bundles and trays. Those systems are governed by percentage visual fill of the opening and the sealant has to be worked in between the cables rather than run as a ring around a single pipe, which takes several times the material this returns.
- Whether the penetration needs a T rating as well as an F rating changes the system, not merely the number. Where a floor penetration has to limit temperature rise on the unexposed side, the listed treatment usually gets deeper or picks up a wrap strip or a device, and the fill depth entered above moves with it.
Estimated cost — your price
This site holds no price list for this material — local prices vary too much to publish honestly. Enter your supplier's price and the result is costed with it.
Part of a bigger job
This trade is one line of a job takeoff. Run the whole job and every other trade comes back with it, off the same measurements.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-06 · in the site-wide review of 2026-09-06 · v1.0.1
Regulatory standards & verification citations1
- Firestop sealant volume = total penetration perimeter × annular gap width × firestop depth, the standard method for estimating a continuous sealant bead around penetration openings
Cite this page
Your workspace
Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.
Tools and safety for this job
To fire-stop the service penetrations. Generic types, no brands, no prices.
Protection this work requires
- Mineral and glass wool irritate skin, eyes and airways: cover your arms, wear a P2/N95 respirator while cutting, and rinse in cold water — hot water drives fibres in.
- Most fatal falls on small jobs are from under three metres: use a tower or a ladder tied at the top, and never work off the top two rungs.
- Knives cause more site injuries than any power tool: cut away from your body, change blades often, and wear cut-resistant gloves to EN 388 level C for repeated cutting.
Fire-stop the service penetrations: Which walls and floors separate one fire compartment from another, and which tested product seals a given penetration through them, come from the fire strategy or the building-control drawings and the product's test evidence. This site does not certify fire-stopping or say which rating applies; it counts the penetrations and the sealant.
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Essential
Caulking gun
Tape measure
Utility knife
Recommended
Step ladder
Also needed as materials: caulk and sealant cartridges, replacement blades.
what each fire-protection tool is for, and the spec that decides which to buy where one does.