Switches for smoke detectors, SO₂ qualified, according to European standards

Smoke detectors save thousands of lives every year. If the switches and other components within these smoke detectors are faulty or work intermittently, there can be serious consequences. According to European standards, all smoke detectors need to be compliant with IEC 60068-2-42:2003, which is the Sulphur Dioxide test for contacts and connections. Compliance can be tested either at the system level or the switch level.

This protocol calls for a rigorous four-day test, putting the smoke detectors in an environment with a temperature of 25°C, a SO₂ concentration of 25x10^-6 and relative humidity of 93 percent. Once they have successfully passed the test, the smoke detectors receive the SO₂ qualification, meaning they are compliant with the European standards.

Since this qualification can also be given at the switch level, C&K has pre-qualified some of its products to the IEC 60068-2-42:2003 standards so they can be integrated into any smoke detector in Europe.

C&K has qualified 43 references across seven series, available in different sizes and with very different features. They have successfully passed the SO₂ test and are compliant with the SO₂ qualification at the switch level. In smoke detectors, the KMR, KMT0, KSC, KSE, PTS530 and PTS810 series are usually used as reset or test buttons, while the RTE series is used to identify the location of smoke detectors on premise.

The KMR series has eight products SO₂ qualified, which include the below main features:

 ultra-low consumption

operating life of up to 300,000 cycles

customization, due to flexible manufacturing (different heights, forces, contact material and life cycles)

The KMT0 series offers six products compliant with the SO₂ qualification which include the following benefits:

operating life ranging from 300,000 to 1 million cycles

ultra-low current versions which allow an increased battery lifetime

IP68 sealed

C&K’s various KSC series offer 18 SO₂ qualified references, which feature:

top or side actuated switches with a life cycle ranging from 100,000 to 5 million cycles

customization, due to flexible manufacturing (different heights, forces, contact material and life cycles)

detect versions

Four products of the KSE low profile tact switch series are SO₂ qualified and are characterized by:

cost optimized solution

IP67 sealed switches

operating life of 300,000 cycles

The PTS530 series is composed of ultra-low profile SMT top actuated switches, including 3 SO₂ qualified products that include:

cost optimized solution

0,55mm thickness

operating life of up to 1 million cycles

Meanwhile, the PTS810 series has also two SO₂ qualified products that offer:

cost optimized solution

different forces up to 6N

cycle life of 150,000 cycles.

Two RTE references have also been successfully SO₂ qualified. These low profile rotary DIP switches:

feature a miniature size with robust stainless steel cover

allow rotary binary-decimal and hexadecimal coding

offer up to 20,000 actuations

C&K also offers additional products that can be integrated in smoke detectors and are compliant with these regulations when the system in which they are installed is sealed against SO₂.