Manufactured Curbs AHA (Activity Hazard Analysis / Job Hazard Analysis)
Updated 2026-06-23
A Manufactured Curbs AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan that keeps the crew installing manufactured curbs safe from the at-height roof and opening fall, from the curb handling and sharp edge, and around the fastening, sealing, and flashing. Manufactured curbs installs prefabricated roof curbs — combining the at-height-roof and opening-fall hazard, the curb-handling and sharp-edge hazard, and the fastening-sealing and flashing hazard. This guide walks through building a Manufactured Curbs AHA that names the at-height-roof/opening- fall, curb-handling/sharp-edge, and fastening-sealing/flashing hazards and assigns the fall, handling, and fastening controls that hold up in the field.
Why manufactured curbs needs its own AHA
Manufactured curbs is the installation of prefabricated roof curbs — the manufactured roof curbs (factory-made raised frames/platforms mounted on the roof to support and elevate rooftop equipment — HVAC units, fans, skylights, hatches — and to provide a flashing base). This continues the roof-accessories group, focused on roof curbs. The defining feature is that curbs are set on the roof over roof openings (the curb usually goes over an opening in the roof deck for the equipment/duct below — a fall-through hazard at the opening), the work is at height on the roof, and the curbs are bulky/heavy manufactured items (a handling hazard — sometimes hoisted) with sharp metal edges, fastened, sealed, and flashed. The hazards combine the at-height-roof and opening-fall (working on the roof over the curb opening — the fall and fall-through hazards), the curb-handling and sharp-edge (handling the bulky curbs and the sharp edges — the handling and cut hazards), the fastening-sealing and flashing (fastening, sealing, and flashing the curb — the fastening, sealant, and flashing hazards), and the eye. The at-height-roof/ opening-fall and the curb-handling/sharp-edge justify a dedicated AHA.
Breaking manufactured curbs into steps
The steps for a Manufactured Curbs AHA follow the work:
- Assess the roof and the curb opening (fall-through, access)
- Set up roof and opening fall protection
- Hoist/handle and position the curb (bulky, sharp edges)
- Fasten the curb to the roof structure
- Seal and flash the curb in
- Manage the fall, handling, and fastening hazards
- Complete
Each step carries a hazard, and the at-height-roof/opening-fall, the curb-handling/sharp-edge, and the fastening- sealing/flashing are where the most significant risks concentrate.
The hazards step by step
At-height-roof and opening-fall
Working on the roof over the curb opening — the fall and fall-through hazards. The controls are roof and opening fall protection (manufactured curbs are set on the roof over roof openings (the curb usually goes over an opening in the roof deck for the equipment or duct below — a fall-through hazard at the opening until the curb and its cover/equipment are in place), and the work is at height on the roof — so fall protection at the roof edge, opening protection at the curb opening (covers/guards over the deck opening), and safe access), and the fall/opening controls. The at-height-roof/opening-fall is the primary defining hazard — curb work is at height over a roof opening. (These follow the roof-fall and opening-protection fundamentals.)
Curb-handling and sharp-edge
Handling the bulky curbs and the sharp edges — the handling and cut hazards. The controls are curb-handling and sharp-edge controls (manufactured curbs are bulky and can be heavy (a manual-handling hazard — team lifts, and sometimes mechanical hoisting/craning the curb to the roof and into position, with the corresponding rigging/ suspended-load controls for hoisted curbs), and the curbs have sharp metal edges (a laceration hazard — cut- resistant gloves and careful handling)), and the handling/cut controls. The curb-handling/sharp-edge is a defining hazard — curbs are bulky/heavy with sharp edges. (These follow the material-handling and sharp-edge fundamentals.)
Fastening-sealing and flashing
Fastening, sealing, and flashing the curb — the fastening, sealant, and flashing hazards. The controls are fastening-sealing and flashing controls (fastening the curb to the roof structure (fastening tools), sealing it (sealants — the sealant-chemical hazard), and flashing the curb into the roof membrane (flashing work, and any membrane/adhesive or soldering used to flash it in)), and the fastening/flashing controls. The fastening-sealing/ flashing is a defining hazard. (These follow the fastening and flashing fundamentals.)
Eye
The eye (fastening, cutting, sealants) carries the eye hazard. The controls are eye protection (fastening debris, any cutting, and sealant splash), and the eye controls. (These follow the eye-protection fundamentals.)
A simple Manufactured Curbs AHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Assess | Fall / opening | Assess the roof and the curb opening (fall-through, access) | project |
| Fall protection | Fall / opening | Set up roof and opening fall protection | OSHA 1926.501 |
| Hoist/handle | Strain / sharp edge | Hoist/handle and position the curb (bulky, sharp edges) | project |
| Fasten | Fastening | Fasten the curb to the roof structure | OSHA 1926.302 |
| Seal/flash | Chemical | Seal and flash the curb in | OSHA 1926.59 |
| Manage | Fall / handling | Manage the fall, handling, and fastening hazards | project |
Roof/opening fall protection and curb-handling/sharp-edge control
A Manufactured Curbs AHA centers on roof/opening fall protection and curb-handling/sharp-edge control. The roof/ opening fall protection addresses the at-height opening work — controlled by roof and opening fall protection (roof-edge protection, opening protection at the curb opening, safe access). The curb-handling/sharp-edge control addresses the bulky curbs — controlled by curb-handling and sharp-edge controls (team lifts/hoisting with rigging controls, cut-resistant gloves). And the fastening, sealing, flashing, and eye get fastening/flashing and eye controls. An AHA built on roof/opening fall protection and curb-handling/sharp-edge control, with fastening/ flashing controls, addresses the hazards that define manufactured curbs.
From the field: what actually goes wrong
In fourteen years across federal, heavy civil, and industrial projects, manufactured curbs installs the factory- made roof curbs (raised frames/platforms) that support and elevate rooftop equipment and provide a flashing base, and its defining hazards center on the roof opening the curb sits over and the bulk of the curb. The at-height-roof and opening-fall hazard is a primary defining concern — manufactured curbs are set on the roof over roof openings (the curb usually goes over an opening in the roof deck for the equipment or duct below, a fall-through hazard at the opening until the curb and its cover or equipment are in place), and the work is at height on the roof, so fall protection at the roof edge, opening protection at the curb opening (covers or guards over the deck opening), and safe access are central. The at-height work over the roof opening is the defining hazard.
The curb-handling/sharp-edge and the fastening-sealing/flashing are the other defining hazards. On the projects I have run, manufactured curbs are bulky and can be heavy (a manual-handling hazard — team lifts, and sometimes mechanical hoisting or craning the curb to the roof and into position, with the corresponding rigging and suspended-load controls for hoisted curbs), and the curbs have sharp metal edges (a laceration hazard — cut- resistant gloves and careful handling). And the fastening-sealing/flashing hazard is fastening the curb to the roof structure (fastening tools), sealing it (sealant-chemical), and flashing it into the roof membrane (flashing work, and any membrane/adhesive or soldering used to flash it in). The eye hazard rounds it out. The AHA built on roof/opening fall protection and curb-handling/sharp-edge control is the one that protects the curb crew.
The bottom line
A Manufactured Curbs AHA names the at-height-roof/opening-fall, the curb-handling/sharp-edge, and the fastening- sealing/flashing hazards with specific controls — roof and opening fall protection (roof-edge protection, opening protection at the curb opening, safe access), curb-handling and sharp-edge controls (team lifts/hoisting with rigging controls, cut-resistant gloves for the sharp edges), and fastening-sealing and flashing controls (safe fastening, sealant-chemical safety, flashing-in safety). The roof/opening fall protection and the curb-handling/ sharp-edge control are the defining concerns. The AHA that manages both is the one that protects the crew.
Frequently asked questions
Why is the roof/opening fall the defining hazard?
Manufactured curbs are set on the roof over roof openings (the curb usually goes over an opening in the roof deck for the equipment/duct below — a fall-through hazard at the opening until the curb and its cover/equipment are in place), at height. Controls are roof and opening fall protection (fall protection at the roof edge, opening protection at the curb opening — covers/guards over the deck opening; safe access), and the fall/opening controls.
What handling and sharp-edge hazards apply?
Manufactured curbs are bulky and can be heavy (a manual-handling hazard — team lifts, and sometimes hoisting/craning to the roof), and the curbs have sharp metal edges (a laceration hazard). Controls are curb-handling and sharp-edge controls (team lifts, mechanical hoisting with rigging/suspended-load controls for hoisted curbs, cut-resistant gloves and careful handling), and the handling/cut controls.
What fastening, sealing, and flashing hazards apply?
Fastening the curb to the roof structure (fastening tools), sealing it (sealants), and flashing it into the roof membrane (flashing work, and any membrane/adhesive or soldering used to flash it in). Controls are fastening-sealing and flashing controls (safe fastening, sealant-chemical safety, flashing-in safety), and the fastening/flashing controls.
What is manufactured curbs?
Manufactured curbs is the installation of prefabricated roof curbs — the manufactured roof curbs (factory-made raised frames/platforms mounted on the roof to support and elevate rooftop equipment and provide a flashing base). Because the work is at height over a roof opening (fall and fall-through), the bulky curbs are a handling hazard with sharp edges, and they are fastened, sealed, and flashed in, those hazards apply.
Related AHAs and JHAs
- Roof Accessories AHA — the roof-accessories fundamentals
- Roof Hatches AHA — the related roof hatches
- Manufactured Roof Expansion Joints AHA — the related manufactured roof items
- Roof Curb Installation JHA — the roof-curb fundamentals
Written by Mustafa Tok, CSP, ASP, CHST — OSHA Authorized Outreach Trainer with 14+ years of international construction safety experience across federal, heavy civil, and industrial projects.