Type 51B: Thermal actuators with pushing action, for fire dampers, operated by thermal glass bulb


These mechanical thermal actuators are intended to close the fire dampers used on the ventilation ducts. Their large operating force unlocks the spring actuating the damper. Requiring no power supply, these devices are particularly simple and reliable.

They are mandatory for all fire dampers to meet the NF-S 61.937 standard. Since thermal bulbs are not subject to creep, their periodic replacement is not necessary.


Length (A) of the actuating rod before release: 5, 10 or 15mm

Stroke of the actuating rod when triggering: ≥ 20 mm

Pushing force of the actuating rod: ≥ 15 DaN (at the beginning of the stroke)

Communication with the external environment: The mechanisms are equipped with a low leakage wall, separating the air of the ventilation duct from that of the external environment.

Installation: Through the wall of the ventilation duct, with M4 screws or self-tapping screws of similar dimensions. See the metal sheet cutting drawing above.

Body material: PA66 glass fiber reinforced, withstands temperature 200 C

Mechanism material: Stainless steel Aisi 304

ROHS compliance: These mechanisms are ROHS compliant.

Identification: Model and date of manufacture are stamped on each mechanism. When equipped with a thermal bulb, it has its own color identification (see the data sheets of the thermal bulbs).

Salt spray resistance: According to ISO 9227-2012, subjected to a mist formed of 20% by weight of sodium chloride in distilled water, at 35°C for 5 days (120h), the mechanisms retain their aptitude for the function.


2D&3D Drawing

Main references

Temperature Length A Reference Length A Reference Length A Reference
Without thermal bulb 5mm 51B2006215PA0000 10mm 51B2006215PB0000 15mm 51B2006215PC0000
57°C (135°F) 5mm 51B20062152A0570 10mm 51B20062152B0570 15mm 51B20062152C0570
68°C (155°F) 5mm 51B20062152A0680 10mm 51B20062152B0680 15mm 51B20062152C0680
79°C (174°F) 5mm 51B20062152A0790 10mm 51B20062152B0790 15mm 51B20062152C0790
93°C (199°F) 5mm 51B20062152A0930 10mm 51B20062152B0930 15mm 51B20062152C0930
141°C (286°F) 5mm 51B20062152A1410 10mm 51B20062152B1410 15mm 51B20062152C1410