Type 58Z: High load breakable glass bulb heat responsive link for heavy loads



Patented mechanical system of fire detection by liquid filled glass bulb breaking. In case of fire, when the temperature reaches the liquid boiling temperature, it causes the explosion of the glass bulb, which releases the mechanism. This self-powered mechanism does not require power supply such as electricity or compressed air. It can open smoke vents, skylights, in buildings, but also actuate fire doors, air conditioning dampers, store curtains, flammable gas or liquid valves, range hood exhausts, paint and solvent exhaust fans and dampers, etc.


Dimensions: Small foot print, can replace most of devices using fusible links. In addition, having a very high tensile strength, this device requires no auxiliary strength demultiplication system.

Creep sensitivity: Insensitive to creep, even close to the tripping temperature.

ROHS compliance: For most of temperature calibration, fusible fire detection systems cannot be achieved, as they use alloys containing lead and cadmium, materials that are not allowed by the RoHS standard. This glass bulb operated device does not use fusible alloy and therefore contains no prohibited metal and meets the RoHS standard.

Material: Galvanized steel

Fail safe operation: When opening, the internal lever falls unhindered by any other part, irreversibly releasing the two halves of the mechanism.

This mechanism has no spring because, due to their susceptibility to corrosion and to permanent deformation, the use of springs may cause a malfunction.

Heat responsive bulbs: glass, dia. 5mm, 20mm nominal length, filled with alcohols blends. They are protected against hits.

Response time index (RTI) of bare bulbs: 90 m.s1/2

Maximum permanent load: 200 DaN Tensile strength at break: ≈350 DaN (120 DaN for the stainless steel type)

Minimum load: 10 DaN

Nominal opening temperatures: 57 °C (135 °F) orange bulb; 68 °C (155° F) red; 79 °C (175 °F) yellow; 93 °C (200 °F) green; 141 °C (285°F) blue; 182 °C (360 °F) mauve. The bulb coloring complies with EN 12259-1 and ISO 6182-1 international standards for color/temperature ratings. Other temperatures, consult us.

*Options:  Rope thimble assembled on one hole. Caution: this thimble may be destroyed by high loads.

Mounting position: When used in vertical position, the glass bulb must be downside. No preferential position when mounted horizontally.

Glass bulb replacement: Replacement is possible, by using a locking pin, which must be removed after bulb replacement.

Certifications: according to ISO 10294-4.

Other types: for load ≤150DaN, see 58L type.


Main references

Temperature (°C/°F)

2 holes dia.8mm, without rope thimble 2 holes  dia. 8mm, downside with rope thimble
57°C (135°F) 58ZFA08300B057C0


68°C (155°F)

58ZFA08300B068C0 58ZFA08300B068C1
79°C (175°F) 58ZFA08300B079C0


93°C (200°F)

58ZFA08300B093C0 58ZFA08300B093C1
141°C (285°F) 58ZFA08300B141C0


182°C (360°F)





2D&3D Drawing