1 Scope
NOTE This standard covers the materials, performance, fabrication, and installation requirements for factory-fabricated roof hatches and gravity smoke and heat exhaust vents that penetrate the roof deck. (1.1)
NOTE The assemblies addressed share a common construction logic — an insulated metal curb, a hinged or releasing cover, weatherproofing hardware, and an integral flashing collar — even though their purpose ranges from routine personnel access to life-safety smoke exhaust. (1.2)
NOTE Three families are covered: personnel and equipment roof hatches (single- and double-leaf), gravity smoke and heat vents (dome and double-skin panel types), and combination access-plus-smoke-vent units. (1.3)
1.4 Assembly Boundary
NOTE The roof hatch or smoke vent assembly comprises the curb, the cover or vent leaf, all operating and latching hardware, factory-applied insulation, and the integral flashing collar furnished by the unit manufacturer. (1.4.1)
NOTE The unit curb is furnished by the hatch or vent manufacturer as part of the assembly; the roofing contractor sets the unit and integrates the base flashing per
Membrane Roofing.
(1.4.2) 1.4.3The hatch or vent shall be furnished as a single factory-assembled and factory-tested unit, not field-assembled from loose components.
1.4.4Curb, cover, and flashing collar shall be furnished by a single manufacturer as a coordinated assembly.
1.5 Exclusions
NOTE Membrane base flashing, stripping plies, and waterproofing at the curb are roofing scope under
Membrane Roofing and are not furnished with the unit.
(1.5.1) NOTE Fan-powered mechanical smoke exhaust, stairwell pressurization, and dedicated mechanical exhaust systems are mechanical contractor scope and are outside this standard. (1.5.3)
NOTE Glazed daylighting units and skylight-based operable smoke exhaust are governed by
Skylights.
(1.5.4) 2 Referenced Standards
2.1Equipment, materials, and installation shall comply with the latest adopted edition of each of the following unless a specific edition is cited.
NOTE Where referenced standards conflict, the more stringent requirement shall govern unless the Engineer of Record directs otherwise in writing. (2.2)
| Standard |
Title |
| UL 793 |
Automatically Operated Roof Vents for Smoke and Heat |
| FM 4430 |
Approval Standard for Heat and Smoke Vents |
| NFPA 204:2021 |
Standard for Smoke and Heat Venting |
| IBC Section 910 |
International Building Code (Smoke and Heat Removal) |
| IBC Section 1013.6 |
International Building Code (Roof Access) |
| IBC Section 712 |
International Building Code (Vertical Openings in Fire-Resistance-Rated Assemblies) |
| UL 10B |
Fire Tests of Door Assemblies |
| ASHRAE 90.1 |
Energy Standard for Buildings Except Low-Rise Residential Buildings |
| IECC |
International Energy Conservation Code (envelope air leakage) |
| NFPA 1 |
Fire Code |
| ASCE 7 |
Minimum Design Loads and Associated Criteria for Buildings and Other Structures |
| ASTM A653/A653M |
Steel Sheet, Zinc-Coated (Galvanized) by the Hot-Dip Process |
| ASTM B209 |
Aluminum and Aluminum-Alloy Sheet and Plate |
| ASTM A240/A240M |
Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip |
| AAMA 2604 |
Performance Requirements for High-Performance Organic Coatings on Aluminum Extrusions and Panels |
| AAMA 2605 |
Performance Requirements for Superior-Performing Organic Coatings on Aluminum Extrusions and Panels |
3 Submittals
3.1 Action Submittals
3.1.1The Contractor shall submit the following action submittals for review prior to fabrication:
- Product data for each hatch and vent type, including curb construction, cover construction, insulation type and R-value, and hardware.
- Shop drawings showing curb dimensions, clear opening, curb height, flashing collar profile, and anchorage to the roof deck.
- A roof opening schedule identifying each unit by type, size, clear opening, fire rating, and location.
- For smoke and heat vents, the UL 793 or FM 4430 listing, published aerodynamic (net) free area, and fusible-link rating for each unit.
- For fire-rated hatches, the UL 10B listing and label evidence for the rating scheduled.
- Manufacturer color charts and finish samples where a factory coating is specified.
☐ Product data (curb, cover, insulation, hardware)
☐ Shop drawings (dimensions, curb height, flashing collar, anchorage)
☐ Roof opening schedule (type, size, rating, location)
☐ Smoke vent listing + aerodynamic free area + fusible-link rating
☐ Fire-rated hatch UL 10B listing and label evidence
☐ Finish samples / color charts
3.2.1The Contractor shall submit the following informational submittals:
- Engineered smoke and heat venting calculations per NFPA 204 or the IBC 910 prescriptive ratio, signed by the Engineer of Record where an engineered design is used.
- Structural load data confirming cover live-load and unit snow and wind ratings for the project design loads.
- Manufacturer installation instructions and curb-to-roofing interface details coordinated with the roofing manufacturer.
☐ Smoke vent venting calculations (NFPA 204 or IBC 910 ratio)
☐ Structural load data (cover live load, snow, wind)
☐ Installation instructions + curb interface details
3.3 Closeout Submittals
3.3.1The Contractor shall submit the following closeout submittals:
- Operation and maintenance data, including hardware adjustment and fusible-link replacement procedures for smoke vents.
- Written warranty documents executed in the Owner's name.
- Record documentation of the as-installed roof opening schedule.
☐ Operation and maintenance data
☐ Executed warranty documents
☐ As-installed roof opening schedule
4 Quality Assurance
4.1 Listings and Labeling
4.1.1Gravity smoke and heat vents shall be listed and labeled to UL 793, or approved to FM 4430 where the project is FM Global insured.
4.1.2On FM Global insured projects, smoke and heat vents shall carry FM 4430 approval; a UL 793 listing alone is not an acceptable substitute.
NOTE UL 793 and FM 4430 are independent listing pathways with different test protocols; substituting one for the other without the insurer's written approval is a common cause of submittal rejection on FM-insured work. (4.1.3)
4.1.4Fire-rated roof hatches shall be listed and labeled to UL 10B for the fire-protection rating scheduled.
4.1.5Each unit shall bear the permanent label of the listing agency corresponding to its scheduled rating.
4.2 Manufacturer Qualifications
NOTE Units shall be the standard catalog product of a manufacturer regularly engaged in the production of factory-fabricated roof hatches and smoke vents. (4.2.1)
4.2.2Each unit shall be factory cycle-tested for proper operation of the cover, hold-open hardware, and latching before shipment.
4.2.3Smoke and heat vents shall be production-tested to the requirements of their UL 793 or FM 4430 listing.
5 Environmental and Service Conditions
5.1 Structural Loads
NOTE Cover and curb structural ratings shall equal or exceed the roof live, snow, and wind loads established for the project under ASCE 7. (5.1.1)
5.1.2The cover shall be rated for a live load of not less than the scheduled value to support personnel and incidental loads during access.
NOTE Spring-assisted covers on exposed roofs can act as a sail and be damaged by wind uplift when held open; cover opening direction shall be coordinated with building orientation and prevailing wind. (5.1.3)
5.1.4The cover opening direction shall be oriented so the open cover does not face the prevailing wind on exposed rooftops.
5.2 Corrosion Environment
NOTE Coastal, high-humidity, and chemically aggressive environments accelerate corrosion of galvanized steel; aluminum or stainless steel is preferred where service conditions are corrosive. (5.2.1)
5.2.2Curb and cover material shall be selected for the project service environment.
● Normal interior/exterior commercial
○ Coastal / marine (salt exposure)
○ Corrosive / chemical process
5.3 Energy and Air Barrier Compliance
NOTE A factory-insulated cover with an R-value below the surrounding roof assembly creates an energy-code deficiency that is commonly missed at permit; cover insulation shall meet or exceed the adjacent roof assembly minimum. (5.3.1)
5.3.2Cover and curb insulation R-value shall equal or exceed the minimum required for the surrounding roof assembly under ASHRAE 90.1 for the project climate zone.
5.3.3The curb-to-roof interface shall maintain continuity of the building air barrier.
5.3.4The curb perimeter shall be sealed to the air barrier to limit envelope air leakage.
NOTE Interrupting the air barrier at the curb-to-roof interface is a common energy-code deficiency; continuity must be maintained for the assembly to meet the adopted IECC envelope air-leakage limits. (5.3.5)
5.3.6The curb shall be gasketed or sealed to the roof air barrier to maintain envelope air-leakage compliance under the adopted IECC.
6 Hatch Types and Configuration
NOTE The selection of hatch type is driven by the access function: personnel-only access, equipment or material passage, or combined access with automatic smoke release. (6.1)
NOTE Personnel hatches serve ladder or stair access for a single person and use the smallest practical clear opening; equipment hatches provide a larger clear opening for material handling. (6.2)
6.3 Hatch Type
6.3.1The hatch shall be furnished as the scheduled type and leaf configuration.
● Single-leaf personnel hatch
○ Double-leaf personnel hatch
○ Single-leaf equipment hatch
○ Double-leaf equipment hatch
○ Combination access / smoke vent
6.4 Clear Opening
NOTE Most codes establish a minimum personnel access opening of 30 in. × 36 in.; the 36 in. × 36 in. opening is the prevailing default and accommodates a person with hand tools. (6.4.1)
6.4.2The clear opening shall not be less than the code-required minimum for the access type served.
○ 30 × 36
● 36 × 36
○ 30 × 54
NOTE Equipment hatches require an opening sized for the largest item passed; openings above roughly 48 in. × 96 in. are custom-fabricated. (6.4.3)
○ 36 × 48
○ 48 × 48
● 48 × 72
○ 48 × 96
6.4.4Where the equipment hatch clear opening exceeds the manufacturer's largest standard catalog size, the unit shall be custom-fabricated to the dimensions indicated. equipment hatch opening dimensions 6.5 Cover and Curb Material
NOTE Galvanized steel is the economical default; aluminum reduces weight and resists corrosion; stainless steel is reserved for severe corrosive service. (6.5.1)
6.5.2Curb and cover shall be fabricated from the scheduled material with the curb and cover of the same material unless dissimilar-metal isolation is provided.
● Galvanized steel (ASTM A653 G90)
○ Aluminum (ASTM B209)
○ Stainless steel (ASTM A240)
6.5.3Galvanized steel sheet shall be hot-dip zinc-coated to ASTM A653 with a G90 coating designation minimum.
6.5.4Where dissimilar metals contact, the manufacturer shall provide isolation to prevent galvanic corrosion.
6.6 Curb Height
NOTE A standard 12 in. curb measured above the roof deck is correct only where the finished membrane is near the deck plane; most single-ply membrane manufacturers require at least 8 in. of flashing height above the finished roof surface, so the curb must be taller where insulation thickness is significant. (6.6.1)
6.6.2Curb height shall provide not less than 8 in. of base-flashing height above the finished roof surface.
6.6.3In heavy-snow regions and on dead-flat roofs subject to ponding, the curb height shall be increased so the flashing height is maintained above the design snow or ponding depth.
6.7 Insulation
6.7.1The curb walls and cover shall be factory-insulated to the scheduled R-value.
NOTE Insulation shall be a non-wicking type — rigid polyisocyanurate or encapsulated fiberglass — protected by a metal liner on the cover interior. (6.7.2)
6.7.3The cover insulation shall be enclosed by a metal liner pan and shall not be left exposed on the cover underside.
7 Hardware
NOTE Roof hatch hardware shall permit one-person operation from inside and provide positive holding of the open cover against incidental wind. (7.1)
7.2 Hold-Open Hardware
7.2.1The cover shall be equipped with a hold-open arm or compression-spring mechanism that automatically locks the cover in the full-open position.
● Compression-spring operators with hold-open arm
○ Telescoping tube hold-open arm
○ Gas-spring operators
NOTE The hold-open arm shall include a release handle that allows the cover to be closed in a controlled manner without freefall. (7.2.2)
7.2.3The hold-open mechanism shall require a deliberate manual release to disengage and shall not release under wind load alone.
7.3 Latching and Security
7.3.1The cover shall be fitted with a latch operable from both the interior and the exterior.
☐ Interior turn handle / slam latch
☐ Exterior padlock hasp
☐ Keyed cylinder lock
☐ Interior padlock provision
7.3.2A spring-latch shall automatically engage when the cover is closed to secure the unit against wind uplift.
7.3.3Where security is required, the cover shall include an exterior padlock hasp or keyed lock as scheduled.
7.4 Weatherproofing
NOTE The cover shall close against a continuous compressible gasket to seal the cover-to-curb joint against wind-driven rain. (7.4.1)
7.4.2The cover-to-curb joint shall be gasketed with a continuous closed-cell or EPDM gasket.
7.4.3The curb shall include an integral overlapping cap flange that sheds water over the base flashing.
8 Gravity Smoke and Heat Vents
NOTE Gravity smoke and heat vents are passive life-safety devices that open automatically on a thermal signal to exhaust smoke and heat through the roof, limiting smoke-layer descent and aiding firefighter access. (8.1)
8.2 Application Basis
NOTE IBC Section 910 requires gravity smoke and heat venting for designated factory and storage occupancies; NFPA 204 governs the engineered design of the vent system. (8.2.1)
8.2.2Smoke and heat vents shall be provided where required by IBC Section 910 or the engineered fire-protection design.
NOTE NFPA 204 gravity-vent design criteria are valid only for unsprinklered occupancies; applying them to an ESFR-sprinklered building is incorrect because ESFR systems require vents to remain closed at activation to develop suppression pressure, and IBC Section 910 exempts ESFR-protected areas from the vent requirement. (8.2.3)
8.2.4Gravity smoke and heat vents shall not be specified within ESFR-protected storage areas exempted under IBC Section 910.
8.3 Vent Type
8.3.1The vent shall be furnished as the scheduled type.
○ Thermoplastic dome, single
○ Thermoplastic dome, double
○ Double-skin insulated panel, single-leaf
● Double-skin insulated panel, double-leaf
○ Acoustical double-skin panel (STC-rated)
NOTE Acoustical double-skin vents provide an STC-rated panel for warehouses adjacent to noise-sensitive uses where a plain dome would be a flanking path. (8.3.2)
8.4 Vent Area and Spacing
NOTE Manufacturers publish an aerodynamic (net) free area well below the nominal unit dimension; specifying only the gross unit size leads to under-ventilated designs that fail IBC 910 compliance. (8.4.1)
8.4.2Required vent area shall be expressed and verified as aerodynamic (net) free area, not gross unit dimension.
NOTE The prescriptive IBC 910 vent-to-floor-area ratio is 1:100 for storage height 12 ft or less and 1:75 for storage height greater than 12 ft; an engineered NFPA 204 design may establish a different ratio. (8.4.3)
● IBC 910 prescriptive 1:100 (storage height ≤ 12 ft)
○ IBC 910 prescriptive 1:75 (storage height > 12 ft)
○ Engineered NFPA 204 design
8.4.4Maximum spacing between vents shall not exceed 200 ft or 12 times the design smoke-layer depth, whichever is governed by the NFPA 204 engineered design.
8.5 Draft Curtains
NOTE NFPA 204 requires draft curtains to bound vent groups and limit lateral smoke spread; designers frequently specify the vents but omit the draft curtain depth and framing, leaving it uncoordinated between the structural and roofing trades. (8.5.1)
8.6 Automatic Activation
NOTE UL 793 requires the vent to operate automatically and independently of building power; the cover shall open by gravity or stored mechanical energy on a thermal signal. (8.6.1)
8.6.2The vent shall open automatically on a fusible-link or thermoplastic thermal signal without reliance on building electrical power.
○ Thermoplastic self-opening dome
● Fusible link with compression-spring release
○ Fusible link with stored-gas release
○ Manual-release cable (in addition to automatic)
8.6.3The fusible link rating shall be selected for the ambient service temperature of the space.
NOTE The maximum fusible-link rating permitted under UL 793 is 286 °F; a link rated above the listing maximum shall not be used. (8.6.4)
8.6.5The vent shall reach the full-open position within 5 minutes when tested at 500 °F per the UL 793 protocol.
8.6.6A manual release shall be provided where the design requires firefighter-initiated venting in addition to automatic activation.
9 Fire-Rated Hatch Assemblies
NOTE IBC Section 712 requires a roof hatch that penetrates a fire-resistance-rated roof assembly to be a rated opening protective; specifying a non-rated hatch in a rated assembly is a frequent coordination failure and RFI. (9.1)
9.2 Fire Rating
9.2.1The hatch fire rating shall correspond to the rating of the roof assembly it penetrates.
● Non-rated (unrated roof deck)
○ 20-minute (¾-hour rated roof)
○ 1½-hour (2-hour rated roof assembly)
NOTE A non-rated hatch is acceptable only where the roof deck it penetrates is not a fire-resistance-rated assembly. (9.2.2)
9.2.3Fire-rated hatches shall carry a UL 10B label corresponding to the scheduled rating.
10 Finishes
NOTE The exposed finish shall be selected for durability in the roof environment and for coordination with the building's architectural treatment. (10.1)
10.2 Cover Finish
NOTE Galvanized and stainless covers may be furnished mill-finished; aluminum covers requiring a coordinated color shall receive a factory organic coating. (10.2.1)
10.2.2The cover shall be finished as scheduled.
● Mill / unfinished galvanized
○ Factory prime coat
○ Factory paint (AAMA 2604)
○ High-performance coating (AAMA 2605)
10.2.3Factory organic coatings on aluminum shall meet AAMA 2604 for standard service or AAMA 2605 where superior weathering and color retention are required.
11 Roof Access Coordination
NOTE Where a roof hatch is the sole permanent means of roof access required by IBC Section 1013.6, a companion fixed ladder or stair must be in scope; leaving the ladder as not-in-contract when the hatch is mandatory access is a common omission. (11.1)
NOTE A combination roof hatch / smoke vent must satisfy both the UL 793 smoke-vent listing and the structural cover live-load rating of an access hatch; a plain smoke vent is not rated for personnel loads and shall not be walked on. (11.2)
11.3 Companion Access
11.3.1Where the hatch is the required means of roof access, a permanent fixed ladder or ship's ladder shall be provided and coordinated with the hatch location and swing.
● Fixed vertical ladder (this scope)
○ Ship's ladder / alternating tread (this scope)
○ Roof access stair (separate section)
○ No companion ladder (alternate access exists)
NOTE A safety post or self-closing guardrail gate at the ladder shall be provided to protect the open hatch opening. (11.3.2)
11.3.3A telescoping safety post or guardrail at the hatch opening shall be provided where the hatch serves a fixed ladder.
12 Testing
12.1 Field Operation Test
12.1.1Each installed roof hatch shall be operated through a full open-and-close cycle to verify hold-open engagement, latch function, and weathertight closure.
12.1.2Each installed smoke and heat vent shall be function-tested per the manufacturer's listed procedure to verify automatic release and full-open travel, then reset to the armed position.
12.1.3Defective operation, binding, or failure to seal shall be corrected and the unit retested before acceptance.
13 Installation
NOTE Roof hatch and smoke vent installation interfaces three trades — the unit setter, the roofing contractor, and the sheet-metal contractor — and the curb is the shared boundary; uncoordinated curb height or flashing height is the most common source of leaks. (13.1)
13.2 Mounting and Anchorage
13.2.1The curb shall be mechanically anchored to the structural roof deck or to supplementary framing in accordance with the shop drawings and the project wind-uplift design.
13.2.2Supplementary curb framing shall be provided where the roof opening interrupts deck spans, coordinated with the structural design. roof opening framing 13.2.3Units shall be set level and square so the cover seats uniformly on the curb gasket.
13.3 Flashing Interface
13.3.2The curb shall be set before the roof membrane base flashing is installed so the flashing terminates beneath the curb cap flange.
13.3.4Penetrations through the cover or curb for hardware, conduit, or release cables shall be sealed weathertight.
13.4 Protection and Adjustment
NOTE Installed units shall be protected from construction traffic and debris until substantial completion. (13.4.1)
13.4.2Smoke and heat vents shall not be used as construction access or material hoisting points.
13.4.3Hatch hardware shall be adjusted at completion so covers operate freely and seal fully.
13.4.4Smoke and heat vents shall be left in the armed and labeled position at completion.
14 Delivery, Storage, and Handling
NOTE Units shall be delivered factory-assembled in protective packaging with listing labels and operating instructions attached. (14.1)
14.1.1Units shall be stored off the ground, covered, and protected from weather and physical damage until installation.
14.1.2Smoke and heat vents shall be handled to avoid disturbing the fusible link or release mechanism prior to arming.
14.1.3Damaged covers, curbs, or hardware shall be replaced, not field-repaired, where damage affects weathertightness, structural rating, or the listed operation of a smoke vent.
15 Warranty
15.1The manufacturer shall warrant each roof hatch and smoke vent against defects in materials and workmanship.
15.1.1The warranty shall cover hardware operation, including hold-open arms, springs, latches, and smoke-vent release mechanisms.
NOTE Warranty service for smoke and heat vents shall include restoration of the listed automatic operation following any covered failure. (15.1.2)
16 Spare Parts
NOTE The Contractor shall furnish spare operating components to support post-occupancy maintenance of the installed units. (16.1)
16.1.1The Contractor shall furnish spare fusible links for not less than 10 percent of the installed smoke and heat vents, and not fewer than two of each rating used.
16.1.2The Contractor shall furnish one spare gasket set and one set of hold-open hardware for each hatch type and size installed.
☐ Spare fusible links (≥ 10% of vents, min 2 per rating)
☐ Spare cover-to-curb gasket sets
☐ Spare hold-open arms / springs
☐ Spare latch assemblies