Metal-Framed Skylights AHA (Activity Hazard Analysis / Job Hazard Analysis)
Updated 2026-06-23
A Metal-Framed Skylights AHA (Activity Hazard Analysis / Job Hazard Analysis) is the plan for installing large metal-framed skylight assemblies — the custom atrium, ridge, pyramid, and barrel-vault skylights built from a metal frame filled with glass over a large opening — and it differs from a prefabricated unit skylight in scale: this is a built-up structure rigged and glazed at height over a big hole. This AHA (Activity Hazard Analysis / Job Hazard Analysis) is about erecting and glazing a large overhead assembly.
Why metal-framed skylights needs its own AHA
A metal-framed skylight is a custom, engineered assembly — a structural metal frame (aluminum or steel rafters, purlins, and ridge members) spanning a large roof opening, glazed with numerous or large glass units — forming atrium roofs, ridge skylights, pyramids, and barrel vaults. Unlike a prefabricated unit skylight that drops in as one small piece, this is a built-up structure, and its hazards are those of erecting and glazing a large overhead frame at height. The metal framing members are heavy and are rigged and lifted into place — often crane picks — to be assembled at height into a spanning structure, so it's a structural steel/aluminum erection at height. The glass units are large and heavy and are set into the frame at height, overhead of the space below, so it's at-height glazing of an overhead assembly (glass being lifted and set above people, with falling-glass consequences). And the opening it spans is large — a big fall-through hazard, bigger than a unit skylight's, present through the whole erection until the assembly is complete. So the defining hazards are the rigging and erection of the heavy metal frame at height and the at-height glazing of large units overhead, over a large fall-through opening. This is facade-scale glazed-assembly work turned horizontal and put on the roof.
Breaking metal-framed skylights into steps
The steps are a structural erection plus glazing:
- Confirm the frame design, member and glass weights, and opening from the submittal
- Protect the large roof opening and establish fall protection
- Rig and lift the metal framing members to height (crane/hoist)
- Erect and connect the frame structure over the opening
- Hoist and set the large glass units into the frame at height (overhead)
- Seal, flash, and complete the assembly
- Verify structural completion, glazing, and that no opening is left unprotected
The hazards step by step
Rigging and erecting the heavy metal frame at height
The metal framing members are heavy structural pieces rigged and lifted — frequently by crane — and assembled at height into a spanning frame, so this is a structural erection with all its hazards: the crane pick and rigging (suspended loads, everyone clear, rated gear to the documented weight), the connection work at height (fall protection, working the frame aloft), and the stability of a partially-erected frame over a large opening (bracing until the structure is complete and self-supporting). Rig members to their documented weight, keep clear of suspended loads, work the connections with fall protection, and brace the frame until it's structurally complete — a partly-erected large skylight frame over a big hole is both a fall-through and a structural-stability hazard.
At-height glazing of large units overhead
The glass units are large and heavy and are set into the frame at height, overhead of the space below — so glazing this assembly is a heavy-glass lift performed aloft, with the glass above people and the opening. A dropped or broken large glass unit at height is a severe falling-glass hazard through the assembly to the space below, and the glazing crew works at height handling heavy sharp glass. Hoist and set the glass units with rigging/handling sized to them, control each unit during the overhead set, protect the space below from falling glass, and use fall protection for the glazing crew. This is the facade family's heavy-glass-at-height hazard, oriented overhead on the roof.
The large fall-through opening
The opening a metal-framed skylight spans is large — bigger than a unit skylight's — so the fall-through hazard is substantial and present through the entire erection, until the frame and glazing complete the assembly. Protect the large opening throughout (guarding, covers, or fall protection covering the span as the work allows), keep the crew tied off over the open span, and recognize that until the assembly is structurally complete and glazed, the opening is a large hole. The bigger the skylight, the bigger the hole during construction.
Hoisting, sealant, eye, welding
Crane/hoist operations (rigging fundamentals), any structural welding of a steel frame (hot-work fire/fume/burns), sealants (chemistry), and eye and cut protection throughout.
A simple Metal-Framed Skylights AHA structure
| Step | Hazard | Control | Standard |
|---|---|---|---|
| Rig/lift frame members | Suspended structural load | Crane/rigging rated to weight; clear of loads | OSHA 1926.251 |
| Erect frame at height | Fall / unstable partial frame | Fall protection; brace until structurally complete | OSHA 1926.501 / .751 |
| Glaze large units overhead | Falling glass at height | Hoist/handle to weight; control the set; protect below | OSHA 1926.95 |
| Large opening present | Substantial fall-through | Guard/cover the span; tie off over the opening | OSHA 1926.501(b)(4) |
| Weld frame (if steel) | Hot-work fire/fume | Hot-work permit; fire watch; ventilation; PPE | OSHA 1926.352 |
Where the erection and the glazing both happen at height over the hole
The two defining hazards share the setting: both the frame erection and the glazing happen at height, over a large open span, one after the other on the same assembly. The frame goes up over the hole (rigging and fall hazards), then the glass goes in overhead over the hole (falling-glass and fall hazards) — and through both, the large opening is a fall-through beneath the crew. The unifying control is protecting the open span and tying off the crew throughout the sequence, because from the first frame member to the last glass unit, everyone works at height over a big hole. Managing the opening and fall protection continuously across the erection-then-glazing sequence is what keeps a large overhead assembly from becoming a fall or a dropped-load event.
From the field: what actually goes wrong
The metal-framed-skylight failures are the structural-erection and glazing hazards over the big opening. The erection: a heavy frame member on a crane pick, or a partially-erected frame not yet braced over the large span, and a rigging or stability failure over an open hole. The glazing: a large heavy glass unit set overhead at height, dropped or broken, raining glass through the assembly to the space below — a severe falling-object event because the glass is big, heavy, and above people. And the fall-through: crews working the large open span without continuous protection, one slip from the hole. All are the scale of the assembly — big frame, big glass, big hole, all at height. The controls are structural-erection discipline (rigging, bracing, fall protection), heavy-glass-at-height handling with the space below protected, and continuous protection of the large opening. This is a rigging-and- glazing structure, not a drop-in unit.
The bottom line
A Metal-Framed Skylights AHA is a rigging-and-at-height-glazing plan over a large opening. A custom metal-framed skylight is a built-up structure — heavy metal framing rigged and erected at height, large glass units set overhead into the frame, over a substantial fall-through opening — so the controls are crane/rigging discipline and bracing for the frame erection, heavy-glass-at-height handling with the space below protected, continuous large-opening protection and fall arrest, and hot-work controls for any steel welding. Respect that it's facade-scale glazed- assembly work oriented overhead on the roof, and the large skylight installs safely.
Frequently asked questions
How is a metal-framed skylight different from a unit skylight?
Scale and construction. A unit skylight drops in as one small prefabricated piece; a metal-framed skylight is a large custom-engineered structure — a metal frame spanning a big opening, glazed with numerous or large glass units, forming atriums, ridges, pyramids, and barrel vaults. So its hazards are those of erecting and glazing a large overhead frame at height: rigging heavy framing (often crane picks), setting large glass overhead, and a large fall-through opening — rather than the unit skylight's drop-in-and-don't-fall-through.
What's the hazard glazing at height overhead?
The glass units are large and heavy and set into the frame at height, overhead of the space below, so glazing is a heavy-glass lift performed aloft with the glass above people and the opening. A dropped or broken large glass unit at height is a severe falling-glass hazard through the assembly to the space beneath, and the glazing crew works at height with heavy sharp glass. Hoist and set units with rigging sized to them, control each during the overhead set, protect the space below, and tie off the glazing crew.
Why is the opening a bigger concern than with a unit skylight?
Because a metal-framed skylight spans a large opening — bigger than a unit skylight's — so the fall-through hazard is substantial and present through the entire erection, until the frame and glazing complete the assembly. Protect the large span throughout with guarding, covers, or fall protection as the work allows, keep the crew tied off over the open span, and recognize that until the assembly is structurally complete and glazed, it's a large hole in the roof.
Does erecting the frame involve structural-work hazards?
Yes. The metal framing members are heavy structural pieces rigged and lifted — frequently by crane — and assembled at height into a spanning frame, so it's a structural erection: crane picks and rigging (suspended loads, rated gear, clear zones), connection work at height (fall protection), partial-frame stability over the opening (brace until complete), and hot work if a steel frame is welded (fire, fume, burns). Treat it with structural-erection discipline, not as simple skylight setting.
Related AHAs and JHAs
- Roof Windows and Skylights AHA — the roof-opening group fundamentals
- Unit Skylights AHA — the prefabricated unit skylight comparison
- Glazed Aluminum Curtain Wall AHA — the facade glazed-assembly comparison
- Lifting and Rigging JHA — the frame and glass rigging 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.