Glass Hoistways – Safety and Code Essentials
Glass elevators are increasingly popular in modern architectural design, offering transparency, elegance, and a strong visual impact. But behind the sleek appearance lies a web of technical and regulatory considerations.
Glass hoistways must adhere to strict safety standards:
- Laminated Rated Safety Glass: All panels must be both tempered and laminated. Simply tempered glass does not meet code requirements.
- Individual Panel Certification: In many jurisdictions, each piece of glass must be marked with its certification and rating. Plan for this during fabrication.
- Fire Rating Limitations: Standard glass panels cannot meet fire separation code requirements. This limits their use in buildings with required fire-rated separation between floors.
- UV Protection: Especially relevant for machine room-less (MRL) elevators using rubber-coated belts that degrade under UV exposure. Shop drawings typically specify the required UV resistance.
Structural Design & Ledge Considerations
When designing a structural steel hoistway, several support elements are mandatory:
Elevator Door Header: Unlike traditional builds with drywall or CMU surrounds, glass hoistways need a dedicated header to support door frames.
Ledge Restrictions: Any ledge within the hoistway must not exceed 4 inches in width—except on access walls (e.g. where doors are located).
Transition Areas: Be especially mindful of transitions from concrete to steel hoistways at the pit level or between floors.
Fascia Panels: What They Are and Why They Matter
Fascia panels reduce the vertical clearance between the elevator car and the hoistway, ensuring the gap does not exceed 5 inches – another B44 code requirement.
Options for Fascia Design:
- Standard Sheet Metal – Compliant but obstructs transparency.
- Clear Materials (e.g. Lexan) – Maintains the visual openness but may require code equivalency submissions for fire rating.
- Perforated Metal Panels – Offers some transparency but may face scrutiny from local inspectors.
- True Car Door Interlocks – A more elegant solution that removes the need for fascia altogether, though not all elevator systems support it.
Ventilation and Thermal Control in Glass Systems
With glass hoistways and cabs, ventilation isn’t just a comfort issue—it’s a safety requirement.
Key Requirements:
- Minimum Air Exchange: One full air exchange per hour inside the cab.
- Backup Power for Cab Fan: Must remain operational for at least one hour during power loss.
- Temperature Control: Critical for hoistways exposed to sunlight or outdoor conditions. Mechanical consultants must factor in solar gain and ensure proper climate control.
Glass Elevator Cabs & Doors
The elevator contractor typically provides the cab and doors—but there are still critical design considerations:
- All Glass Surfaces Must Be Laminated & Rated: As with the hoistway, no exceptions.
- Aesthetic Detailing:
- Car Top Shrouds hide the mechanical elements.
- Stainless Steel Cladding can enclose support beams or other components.
- Finish Specifications must be clearly defined—otherwise, you’ll get unfinished (and unsightly) elements.
Glass elevator systems offer striking design opportunities—but they demand thorough coordination between architectural, structural, mechanical, and elevator teams.
Remember:
- Don’t assume your structural engineer and architect know the elevator code.
- Aesthetic decisions can trigger code implications.
- Be proactive with code equivalencies and supplier coordination.
If you’re planning a glass hoistway, we’re happy to provide detailed guidance.