IBC Special Construction: Membrane Structures, Walkways and Awnings

TL;DR — Key Takeaways

• IBC Chapter 31 is a collection of specialized requirements for construction types that have unique characteristics not addressed by the primary occupancy and construction type chapters.

• Membrane structures (§3102): Air-supported, air-inflated, tensioned-membrane, and framed-membrane structures — fabric-covered buildings — must comply with §3102 for occupant load limits, emergency deflation provisions, and structural requirements.

• Temporary structures (§3103): Tents, temporary stages, scaffolding, and seasonal structures are regulated for fire, egress, and structural safety.

• Pedestrian walkways (§3104): Covered walkways connecting buildings (skyways, pedways) must provide fire separation from each connected building and maintain egress requirements along the walkway.

• Solar panels and photovoltaic systems (§3111): Structural support, load requirements, and fire department access around roof-mounted PV arrays are governed by §3111.

• Swimming pools (§3109): Barrier requirements, drain safety (Virginia Graeme Baker Act), and emergency shutoff provisions are required for all swimming pools and spas.

• Signs (§3107): Projecting, roof, and wall signs have specific structural, clearance, and anchorage requirements.

• Automatic vehicular gates (§3110): Safety and entrapment protection provisions for motorized gates at parking garages and drive-through facilities.

Membrane Structures (§3102)

What Is a Membrane Structure?

A membrane structure is a building or structure with a primary roof or wall covering made of a fabric material — tensioned fabric roofs, air-supported domes (sports facilities, warehouses), and temporary inflatable enclosures.

IBC §3102 applies to both permanent and temporary membrane structures. Permanent membrane structures must comply with the full IBC in addition to §3102; temporary membrane structures (less than 180 days) have modified requirements.

Key Requirements for Permanent Membrane Structures

§3102.3 — Membrane and cable materials:

• Membrane covering materials must be flame-resistant per NFPA 701 (Standard Methods of Fire Tests for Flame Propagation of Textiles and Films)

• Cables and structural elements must be designed per the applicable material standard (AISC 360 for steel cables, etc.)

§3102.4 — Structural requirements:

• Membrane structures must be designed for all applicable loads per IBC Chapter 16 — dead, live, snow, wind, seismic

• Air-supported structures must be designed for the minimum internal pressure required to maintain structure against the design wind and snow loads

• A backup inflation system is required for air-supported structures to maintain pressure in case of primary blower failure

§3102.5 — Emergency deflation:

Air-supported structures over 1,000 sq ft in area must be provided with automatic emergency deflation panels — openings that activate when internal pressure drops below a threshold, allowing emergency egress during deflation events.

§3102.7 — Means of egress:

Egress from membrane structures follows standard IBC Chapter 10 requirements — occupant load, exit count, exit width. For structures with flexible membrane walls, egress panels must be readily identifiable and must open easily from the inside without special knowledge or tools.

Pedestrian Walkways (§3104)

Enclosed pedestrian walkways (skyways) connecting buildings above grade level are common in cold-climate downtowns and hospital campuses.

Fire Separation Requirements (§3104.2)

At each building connection, the walkway must be separated from the connected building by a 2-hour fire-resistance-rated wall with 1½-hour rated doors. This prevents a fire in one building from spreading into the walkway and threatening the other building — or vice versa.

The fire-rated separation doors must be self-closing and self-latching. They may be equipped with hold-open devices that release on activation of the fire alarm (electromagnetic hold-open releases).

Egress Through Walkways (§3104.4)

Pedestrian walkways may serve as a component of the required egress system from each connected building — the walk itself becomes an "exit passageway." When used as part of egress:

• The walkway must meet the width requirements for the occupant load it serves

• Travel distance through the walkway counts toward the maximum travel distance from the exit access of each building

• Sprinklers may be required in the walkway per §903

Structural Expansion Joints

Where buildings expand thermally at different rates (buildings of different heights, different orientations, different materials), the skyway structure must accommodate differential movement without damage to the connections, the walkway, or the buildings. Expansion joints in the walkway floor and roof must be detailed to remain weathertight through the full range of movement.

Swimming Pools and Spas (§3109)

Enclosure Requirements (§3109.4)

IBC §3109 requires that outdoor residential swimming pools and in-ground spas be enclosed by a barrier that prevents access by children:

• Barrier height: Minimum 48 inches above grade at all points

• Bottom clearance: Maximum 2 inches between the bottom of the barrier and the ground

• Wall of house as barrier: Permitted in some configurations — but the wall must not have direct door access to the pool without an alarm or self-closing/self-latching mechanism

• Gates: All gates in the barrier must be self-closing and self-latching; the latch must be at least 54 inches above grade or on the pool side of the gate (preventing children from operating it from outside)

Note: These IBC provisions apply to commercial pools. Residential pool barriers may be governed by the IRC (International Residential Code) or local ordinance — many jurisdictions have adopted enhanced pool barrier requirements.

Drain Safety (§3109.3 and Virginia Graeme Baker Act)

Pool and spa drain covers must comply with ASME A112.19.8 (Suction Fittings for Use in Swimming Pools, Wading Pools, Spas, and Hot Tubs) to prevent body entrapment — a life safety hazard where negative pressure at the drain can trap a person underwater.

The federal Virginia Graeme Baker (VGB) Pool and Spa Safety Act (2007) mandates anti-entrapment drain covers for all public pools and requires unblockable drain covers (two or more drains, or a single drain that cannot be fully blocked) for pools deeper than 5 feet.

Rooftop Solar Panels (§3111)

IBC §3111 addresses the structural and building code requirements for rooftop solar photovoltaic (PV) systems.

Structural Support

Solar panel racking systems add load to the building structure. §3111.2 requires that the structural system be designed to support:

• Dead load: Self-weight of panels and racking (typically 3–5 psf)

• Wind: Uplift and lateral pressures per ASCE 7 (panels increase the tributary wind load on the roof)

• Seismic: Lateral forces from panel and racking mass

The structural engineer of record must verify that the existing (or new) roof structure can support the PV system, including adequate connection between the racking and the structural framing.

Fire Department Access (§3111.4)

IBC §3111.4 requires a minimum clear access pathway around the perimeter of rooftop PV systems to allow fire department personnel to access the roof and work near the system:

• 3-foot minimum clear setback from the roof edge at all eaves

• 3-foot minimum clear pathway along ridgelines (for buildings with pitched roofs)

• 4-foot minimum clear access corridor from a roof access door or hatch to the PV array

These clearances allow firefighters to ventilate the roof and conduct operations safely even when solar panels cover much of the roof area.

Temporary Structures (§3103)

Temporary structures (tents, temporary stages, scaffolding, and seasonal enclosures) erected for fewer than 180 days:

§3103.1 — Permit required: A permit is required for any temporary structure exceeding 400 square feet or any tent exceeding 200 square feet.

§3103.2 — Construction documents: Plans must demonstrate compliance with structural loads and fire safety provisions.

§3103.3 — Flame-resistant materials: Tents and membrane materials must meet NFPA 701 fire-resistance requirements.

§3103.4 — Egress: Temporary structures must provide egress in compliance with IBC Chapter 10 for the occupant load, including minimum aisle widths and maximum travel distance to an exit.

Signs (§3107)

Permanent signs attached to buildings — projecting, roof, and wall signs — have structural and clearance requirements under §3107:

• Projecting signs: Must maintain minimum clearance above sidewalks (9 feet per most jurisdictions) and above driveways (15 feet minimum)

• Structural design: Signs must be designed for dead load, wind load, and seismic load per Chapter 16; connections must be engineered

• Illuminated signs: Electrical requirements per NEC Article 600 (Electric Signs and Outline Lighting)

Research Special Construction Requirements for Your Project

Chapter 31 requirements for membrane structures, pedestrian walkways, pools, or solar systems depend on occupancy, jurisdiction, and specific use. Melt Code lets you search IBC Chapter 31 provisions and your jurisdiction's amendments together.

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Frequently Asked Questions

Q: Does my commercial building's solar PV system require a building permit?

Yes. Rooftop solar PV systems require a building permit in virtually all jurisdictions. The permit covers structural adequacy (§3111.2), electrical installation (NEC Article 690), and fire department access (§3111.4). Some jurisdictions have streamlined solar permits for standard residential systems, but commercial projects typically require full documentation.

Q: Does an outdoor restaurant tent need a building permit?

Yes if it exceeds 200 sq ft per §3103.1. The tent must use flame-resistant materials (NFPA 701), provide adequate egress for the occupant load, and be structurally adequate for wind loading. Many jurisdictions require temporary event permits for large tents in addition to or instead of building permits — check local requirements.

Q: What drain cover standard applies to my commercial pool?

ASME A112.19.8 and the federal Virginia Graeme Baker Act requirements apply to all public (commercial) pool drains. Drain covers must be certified to the ASME standard and must be replaced with approved covers if they are worn, broken, or missing. The Virginia Graeme Baker Act is federally mandated and applies regardless of local building code adoption.

Q: Can a skyway be used as a required exit from my building?

Yes — under §3104.4, a compliant enclosed pedestrian walkway may serve as an exit passageway from each connected building. The walkway must be fire-resistance-rated at the connections, wide enough for the occupant load, and the travel distance through the walkway must be counted in the total exit-access travel distance from the building.