SHEV Inspection Protocol Template: Natural Smoke and Heat Exhaust Ventilation (NSHEV)

Why Natural Smoke and Heat Exhaust Ventilation (NSHEV) Systems Require Regular Testing

Natural smoke and heat exhaust ventilation systems (NSHEV) are critical components of passive fire protection. In the event of a fire, they thermally vent hot combustion gases, smoke, and heat upwards. This keeps escape routes clear of smoke and prevents structural damage from extreme heat. To guarantee this life-saving function, regular and professional testing is legally mandated.

Maintenance and inspections must align with recognized technical standards (such as the EN 12101 series, local standards like DIN 18232-2, or VdS guidelines) and manufacturer specifications. A complete SHEV inspection protocol serves as vital proof for building operators, insurers, and local authorities that all safety obligations have been met.

Focus on Control Panel, Triggering, and Power Supply

The heart of any SHEV system is its control unit. It coordinates the complex interaction between trigger devices, emergency power supplies, and the actual exhaust ventilators (NSHEVs). During the inspection, the control panel must be checked for error logs, line faults, and the integrity of the backup power supply.

The triggering mechanism must function flawlessly across all paths and be fully documented in the protocol:

• Manual Triggering: Checking manual call points (break-glass buttons) for physical damage, glass integrity, and correct signal transmission.
• Automatic Triggering: Testing smoke detectors and the interface for remote triggering via the main fire alarm system (FAS).
• Power Redundancy: Verifying emergency batteries or pneumatic CO2 cartridges in accordance with system-specific maintenance schedules and manufacturer guidelines.

NSHEV Units, Supply Air, and Group-Wise Functional Testing

Natural smoke and heat exhaust ventilators (NSHEV) in roofs and facades must open quickly and reliably to clear the designed geometric or aerodynamic cross-section. Therefore, a group-wise functional test of all trigger groups is performed. This test evaluates the actuators, opening movements, and mechanical locks.

A critical factor is the coordination with supply air inlets in the lower parts of the building. Efficient smoke extraction only works if sufficient fresh air can flow in to create thermal convection. The inspection protocol therefore precisely logs the status of supply air interfaces and the actual limit feedback signals of the window and hatch actuators.

Defect Documentation, Logbook Entries, and System Reset

After triggering and testing all groups, the smoke ventilation systems must be safely closed and reset to their standby operating state. This reset process—including replacing single-use items like CO2 cartridges or fusible links—must be documented in the protocol.

Any defects found, such as worn seals, stiff hinges, or degraded batteries, must be recorded with clear priorities. The template provides structured fields to set repair deadlines and schedule necessary follow-up inspections. All entries should be recorded in the system's physical logbook.