Why is one cable not necessarily one firestop opening?
Several penetrants may share an opening, while one route may cross several barriers. The takeoff needs the location and construction of each opening, not only a cable schedule total. Keep unresolved opening details visible rather than assigning every cable a generic seal.
UL's 2024 firestop and joint application guide describes system-specific penetrants and inspection variables including annular space, penetrant size and spacing. This supports using the applicable system evidence for an opening. It does not supply a universal material allowance for electrical takeoffs.
The estimator records scope and quantities from approved inputs. The responsible design and firestop reviewers establish the applicable systems and acceptance. Engineering sign-off is performed only by the registered engineer on the job.
Sources: UL Solutions: Firestop and joint application guide, 2024
Which columns separate the quantities?
Use a location-based opening register alongside the electrical route takeoff. Define the contractual measurement basis before extending a rate: per opening, per system type, per area or another specified unit.
| Quantity or reference | Record separately | Reason |
|---|---|---|
| Opening identity | Barrier location and drawing reference | The same opening is counted once |
| Opening count | Number of distinct reviewed openings | Different from the number of cables |
| Penetrants | Type and count within each opening | Describes the actual arrangement |
| Barrier construction | Approved wall or floor details | System applicability depends on the assembly |
| System reference | Reviewed detail and revision, or unresolved | No generic seal substituted silently |
| Material basis | Approved system dimensions and supplier basis | Opening count alone does not determine consumables |
| Scope responsibility | Supply, installation and inspection boundaries | Avoid omitted or duplicated subcontract scope |
How do opening and cable counts differ?
Illustrative example. A synthetic route has three cables passing together through opening O-01 and one cable through opening O-02. The register has two openings and four cable penetrants. If the project measures this scope per opening, the initial counted quantity is two openings, with both system selections still requiring review. It is not four firestop assemblies merely because there are four cables.
If those same cables cross another barrier downstream, record the additional openings at that barrier. Deduplicate by opening identity and location, not by cable ID. Conversely, do not collapse two physically separate openings because they share one route name.
The example gives no sealant cartridge quantity, installation labour rate or approved fire rating. Those require the actual selected system, dimensions, scope and source basis. A counted opening with an unresolved detail remains an identified allowance or query under the estimate process.
What should a bid review reconcile?
Compare the opening register with route drawings, barrier details and the firestop scope responsibility matrix. Identify routes crossing a barrier without an opening entry and opening entries with no clear electrical scope. Resolve repeated symbols using actual drawing locations.
Check whether sleeves, devices, making good, inspection evidence and other specified components are included in the quotation. Their contractual inclusion cannot be inferred from the word firestop. Retain the supplier's inclusions and exclusions against the reviewed system reference.
When routes or systems change, update the affected opening rows and quantities. Preserve the earlier basis so the estimate change can be explained. Do not treat the register as an installation approval or an inspection certificate.
Common questions
What else should the bid team know?
Can four cables mean two firestop openings?
Yes, in the illustrated arrangement. Count actual openings and record their penetrants separately.
Does an opening count determine sealant consumption?
No. Use the reviewed system geometry and material basis.
Who selects the applicable firestop system?
The responsible authorised design and firestop reviewers under the project process.
Primary sources
- Firestop and joint application guide, 2024UL Solutions