Aspirating detection system and method

1. An aspirating detection system for monitoring an environment, the system comprising:

an aspirating detector for aspirating and detecting smoke in a sample of air;

a sampling pipe for providing a sample of air to the aspirating detector, the sampling pipe at least partially exposed to the monitored environment; and

a heat-detection device exposed to the monitored environment and arranged to emit an airborne substance into the sampling pipe when the temperature of the monitored environment exceeds a predetermined threshold;

wherein the aspirating detector is arranged to detect the airborne substance and thereby detect that the temperature of the monitored environment exceeds the predetermined threshold; and

wherein the heat-detection device is arranged to seal an opening in the sampling pipe to the monitored environment such that only the airborne substance is emitted via the opening into the sampling pipe for detection by the aspirating detector when the temperature of the monitored environment exceeds the predetermined threshold.

2. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is installed on the sampling pipe.

3. An aspirating detection system as claimed in claim 1 , wherein the airborne substance is at least one of an aerosol or a target gas.

4. An aspirating detection system as claimed in claim 3 , wherein the airborne substance is paraffin smoke.

5. An aspirating detection system as claimed in claim 1 , wherein the monitored environment comprises a first volume and a second volume;

wherein the sampling pipe is disposed at least partially in the first volume and at least partially in the second volume;

wherein the heat-detection device is disposed in the first volume; and

wherein the sampling pipe comprises an opening into the second volume for aspirating air from the second volume.

6. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is a first heat-detection device and the airborne substance is a first airborne substance, the system further comprising:

a second heat-detection device arranged to emit a second airborne substance when the temperature of the monitored environment exceeds a second predetermined threshold;

wherein the aspirating detector is operable to detect the second airborne substance; and

wherein the first airborne substance is different from the second airborne substance.

7. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is a heat-detection capsule comprising a portion arranged to structurally fail when the temperature of the monitored environment exceeds the predetermined threshold and thereby release the airborne substance.

8. An aspirating detection system as claimed in claim 7 , wherein the heat-detection capsule further comprises a casing;

wherein the casing and the portion are arranged to encapsulate the airborne substance.

9. An aspirating detection system as claimed in claim 7 , wherein the portion is formed of a polycarbonate material.

10. An aspirating detection system as claimed in claim 7 , wherein the portion is configured to melt when the temperature of the monitored environment exceeds the predetermined threshold.

11. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is a heat-detection capsule.

12. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is a first heat-detection device and the airborne substance is a first airborne substance, the system further comprising:

a second heat-detection device arranged to emit a second airborne substance when the temperature of the monitored environment exceeds a second predetermined threshold;

wherein the aspirating detector is operable to detect the second airborne substance; and

wherein the first airborne substance is the same as the second airborne substance.

13. An aspirating detection system as claimed in claim 1 , wherein the heat-detection device is installed in the sampling pipe.

14. A method of determining that a temperature in a monitored environment has exceeded a predetermined threshold, the method comprising:

providing an aspirating detection system for aspirating and detecting an airborne substance;

arranging a substance or device to seal an opening in a sampling pipe of the aspirating detection system, wherein the substance or device is arranged to emit the airborne substance when the temperature within the monitored environment exceeds the predetermined threshold, and wherein the substance or device is arranged such that only the airborne substance is emitted into the sampling pipe above the predetermined temperature for detection by the aspirating detection system when the temperature of the monitored environment exceeds the predetermined threshold; and

determining in response to the detection of the airborne substance that the temperature in the monitored environment has exceeded the predetermined threshold.

15. A method as claimed in claim 14 , the method comprising:

determining the location of the temperature exceeding the predetermined threshold based on the type of airborne substance detected.

16. A method as claimed in claim 14 , the method comprising:

retrofitting the substance or device to the aspirating detection system.