Bilco NB-50TB - Thermally Broken Roof Hatch, 30" x 54"

The Bilco NB-50TB is a thermally broken roof hatch sized 30-inch by 54-inch designed for ship stair access. It uses aluminum cover and frame, both insulated with approximately 3-inch (75 mm) polyisocyanurate for R-18 thermal performance. The hatch features an extruded EPDM gasket permanently adhered to the cover, heavy-duty pintle hinges with stainless steel hinge pins, a slam latch with interior/exterior handles and padlock hasps, lift assistance via compression spring operators enclosed in telescopic tubes, and an automatic hold-open arm for safe access. It has a fully welded corner design and overlapping flange for weather tightness.

Key Features:

• Thermally broken cover & curb with approx R-18 insulation in both cover and curb
• Aluminum cover/frame (11 gauge) with fully welded corners and overlapping flange for enhanced weather resistance
• EPDM gasket adhered to cover to ensure continuous seal around curb opening
• Heavy-duty 316 stainless steel hinges, compression spring lift-assist, automatic hold-open arm for safety and usability
• Slam latch with interior/exterior handles and padlock provisions; curb features integral cap flashing and Bil-Clip flange mounting

• Size (curb-to-curb): 30″ × 54″ (762 mm × 1372 mm)
• Material: 11 gauge (~2.3 mm) aluminum cover and frame
• Insulation: ~3″ (75 mm) polyisocyanurate in both cover and curb
• Curb height: 12″ (305 mm); includes integral cap flashing
• Flange: 5-½″ (114 mm) mounting flange with 7⁄16″ (11 mm) holes for securing to roof deck
• Live load capacity: 40 psf (195 kg/m²)
• Hardware: Type 316 stainless steel hinges; all other hardware zinc plated/chromate sealed; latch includes interior/exterior turn handles with padlock hasps
• Finish: Mill finish aluminum
• Includes: Cover & curb, gasket, hinges, latch and handles, lift springs, hold-open arm

• Prepare roof opening sized 30″×54″ and ensure existing or built curb is structurally sound.
• Position the NB-50TB hatch over the curb, align mounting flange and ensure overlapping flange and cap flashing are seated properly.
• Secure frame to roof deck using hardware through the specified flange holes.
• Install hinges, spring lift operators, hold-open arm, handles and latch hardware.
• Test opening/closing action, ensure gasket seal, verify latch security and hold-open mechanism operate reliably.

Q: What is the thermal insulation rating of the NB-50TB hatch?
A: Approximately R-18 using polyisocyanurate insulation in both the cover and curb.

Q: What live load rating does NB-50TB support?
A: It is engineered to support 40 psf (195 kg/m²).

Q: What materials are used in its construction and hardware?
A: Cover & frame in 11 gauge aluminum; hinges with type 316 stainless steel pins; latch hardware includes padlock hasps; gasket is EPDM; other hardware is zinc plated or chromate sealed.

Q: Is this hatch suitable for frequent use like ship stair access?
A: Yes. The NB-50TB model is specifically designed for ship stair access applications where frequent use is expected.