Life safety · Daylight · Summer ventilation · Roda · Lamilux · GAL
Smoke and Natural Ventilation Systems to EN 12101-2
In a fire, roof vents open automatically so that smoke and heat leave the building and escape routes stay visible. On every other day the same units provide daylight and summer ventilation. Erdinç Klima sizes Roda SHEV, Lamilux rooflight and GAL ridge ventilation systems by aerodynamic free area, supplies CE-marked products with declarations of performance, installs and commissions them as FORM's solution partner.
A smoke and heat exhaust ventilation system (SHEVS) keeps a smoke-free layer above floor level during a fire, so that people can escape and firefighters can see. In industrial buildings it is normally achieved with natural roof vents opening automatically on detection, sized to EN 12101-2 by aerodynamic free area (Aa) and combined with inlet air openings at low level, smoke curtains and a battery-backed control panel. The same roof units usually serve a second, everyday purpose: natural daylight and summer ventilation, which also provides the exhaust area an evaporative cooling system needs. Erdinç Klima supplies Roda and Lamilux smoke vents and rooflights and GAL natural ventilation with EN 12101-2 declarations of performance, and installs them in Türkiye and for export projects.
What smoke ventilation is for
Smoke, not flame, is what kills people and stops firefighting. A SHEV system exhausts hot smoke through the roof while fresh air enters at low level, maintaining a smoke-free layer between the descending smoke and the floor. The objective is a defined clear height for a defined time, long enough for evacuation and fire service intervention.
SCROLL THE DRAWING →
- 1Roof smoke vents (NSHEV) open automatically and release hot smoke
- 2Smoke layer collects under the roof; its depth depends on vent area and fire size
- 3Low-level inlets admit replacement air; without them the vents cannot extract
- 4Smoke-free layer near the floor keeps escape routes and the fire visible
In a large single-storey industrial building this is almost always done naturally, using buoyancy. Hot smoke rises; if the roof is opened above the fire and air can enter below, a stable flow establishes itself with no fans and no power supply. That independence from electricity is precisely why natural systems are preferred in life-safety applications.
The system is more than the vents. It comprises roof units, smoke curtains or screens dividing the roof into reservoirs, low-level inlet openings, detection, and a control panel with battery backup that must operate when mains power has failed. A specification listing only vents is an incomplete system.
Geometric area vs aerodynamic free area
The number that matters is Aa, the aerodynamic free area, not the physical opening size. A vent's geometric opening is reduced by its own frame, flap geometry and airflow losses, so a unit with 2.0 m² of geometric area may deliver only around 1.2 m² of aerodynamic area. Sizing against geometric area systematically undersizes the system.
Aerodynamic free area is determined by test under EN 12101-2 and declared by the manufacturer. Two vents of identical physical size from different manufacturers can have materially different Aa values, which is exactly why the standard requires the tested figure to be declared rather than calculated.
The specification trap: a tender that asks for a number of square metres of smoke vents without stating whether that is geometric or aerodynamic area invites non-comparable bids. The compliant supplier quoting Aa looks expensive next to one quoting geometric area for the same money. Always specify Aa, and require the EN 12101-2 declaration of performance with the offer.
Natural or powered extraction?
Natural systems are preferred wherever the building geometry allows: no power dependency, no moving machinery to maintain, lower running cost. Powered smoke extraction becomes necessary in basements, enclosed car parks, atria and buildings without adequate roof access, anywhere buoyancy alone cannot establish reliable flow.
| Criterion | Natural (roof vents) | Powered (fans) |
|---|---|---|
| Power dependency | None for extraction | Required — with backup supply |
| Suitable buildings | Single-storey halls, warehouses, factories | Basements, car parks, atria, deep plans |
| Everyday secondary use | Daylight and summer ventilation | None |
| Maintenance | Actuator and control checks | Fan, motor and duct maintenance |
| Running cost | Negligible | Significant if used for daily ventilation |
The second job: daylight and summer ventilation
Roof units specified for smoke ventilation can also serve as daylight rooflights and summer ventilators, opening on temperature to release accumulated heat at ridge level. This double duty is what makes the investment attractive outside the fire case, particularly in halls that overheat in summer.
Combined with an evaporative cooling system this becomes a coherent strategy rather than two unrelated purchases: cool fresh air is introduced at low level, hot air leaves through ridge vents, and the same openings are part of the life-safety system. Exhaust area sized for smoke is usually generous for ventilation purposes as well.
We supply Roda smoke vents, Lamilux rooflights and GAL natural ventilation systems (FORM product group) with control panels, detection interfaces and battery-backed actuators; CO₂ pneumatic or 24 V electric actuation according to the project.
Roda SHEV
Smoke and heat exhaust vents for flat and pitched roofs, EN 12101-2 tested, with daily ventilation function.
Lamilux
Glass rooflights and continuous rooflights combining daylight with certified smoke exhaust flaps.
GAL
Ridge ventilation for high-bay factories and workshops: continuous natural exhaust at the highest point of the roof.
European, Turkish and Gulf regulatory practice
Across Türkiye and the Balkans, SHEV design follows the European route: products CE marked under CPR 305/2011 and tested to EN 12101-2, with sizing to national codes or DIN 18232. In the Gulf, authorities more commonly reference NFPA 204 and civil defence approvals, which use different calculation conventions.
Practically, this means the equipment is often the same but the design submission is not. We supply CE-marked, EN 12101-2 tested products with full declarations of performance; where a project is subject to civil defence approval under an NFPA-based code, the local consultant's calculation governs and we supply to that specification. Tell us which regime applies at enquiry stage and the documentation is formatted accordingly.
Related pages
The other systems on this site, and the Turkish version of this page.
- 07-A
All industrial cooling systems
Evaporative cooling, panel air conditioners, chillers, smoke ventilation and F-Gas compliance from one supplier.
Go to the overview → - 07-B
Evaporative cooling
Ridge vents and roof units double as the exhaust an evaporative system needs.
Evaporative cooling → - 07-C
Turkish version of this page
Smoke exhaust and natural ventilation page in Turkish, with the EN 12101-2 area calculator.
Turkish version →
Frequently asked questions
Free area, sizing, power supply, smoke curtains and maintenance questions from consultants, contractors and building owners.
Send us the building and the applicable code
Roof plan, building height, compartment areas and the regulatory regime. We return a vent schedule with declared aerodynamic free areas. Technical consultation by phone or WhatsApp is free; site visits are quoted.
20+ years · authorised Rittal service partner · Istanbul, Türkiye
- Phone
- +90 216 344 48 19
- +90 532 424 62 19
- info @erdincklima.com
- Address
- Esatpaşa Mah., Binikli Sk., Alibey Apt. No: 2/A-B-C, 34704 Ataşehir / İstanbul
- Hours
- Mon–Fri 09:00–18:00 · Sat by appointment
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