HEAT DETECTORS FOR USE IN FIRE ALARM IS : 2175-1988

Indian Standard
SPECIFICATION FOR HEAT SENSITIVE FIRE DETECTORS FOR USE IN AUTOMATIC FIRE ALARM SYSTEM

IS : 2175-1988

(Reaffirmed 2000)

REAFFIRMED 2010

1. SCOPE

1.1

This standard covers the general requirements, test methods and performance requirements for heat sensitive (point) detectors for use in automatic fire alarm system.

2. TERMINOLOGY

2.0

For the purpose of this standard, the following definitions shall apply.

2.1

Control and Indicating Equipments—Unit(s) containing the controls, relays, switches and associated circuits necessary to:

1. provide power,
2. receive signals from alarm indicating (activation devices) and transmit them to the fire alarm devices and control for automatic fire protection equipment, and
3. electrically supervise the system circuitry.

2.2

Detachable Detector—A detector designed to be easily removed from its normal operating position for maintenance and servicing purposes.

2.3

Fixed Temperature Heat Sensitive Detector—A detector designed to operate when the temperature of detector exceeds a predetermined value.

2.4

Line Detector—A linear form of detector in which the detection process may take place anywhere along its length.

2.5

Non-Detachable Detector—A detector not designed to be easily removed from its normal operating position for maintenance and servicing purposes.

2.6

Non-Resettable (Non-Restorable) Detector—A detector which after response requires the renewal of component or components to restore it to its normal state of readiness to detect.

2.7

Point (Spot) Type Detector—A detector in which the sensing element is essentially of a compact area.

2.8

Rate of Temperature Rise-cum-Fixed Temperature Heat Sensitive Detector—A detector designed to operate within a given time:

1. when the rate of temperature rise at the detector exceeds a predetermined value regardless of the actual temperature, and
2. when the temperature at the detector exceeds a predetermined value.

2.9

Resettable (Restorable) Detector—A detector which after response and on cessation of the conditions that caused the response, may be restored from its alarm state to its normal state of readiness to detect without the renewal of any components.

3. TYPES AND GRADES

3.1

Heat sensitive detectors (both resettable and non-resettable) covered in this standard are of the following types:

1. Fixed temperature detector, and
2. Rate of temperature rise-cum-fixed temperature detector.

3.1.1

Each of the above detectors are subdivided into three grades based on the response time (see 5.2) as Grades 1, 2 and 3.

4. GENERAL REQUIREMENTS

4.1

The detector shall be provided with means for mounting (on ceiling/wall) securely and independent of any support from the attached wiring. The heat sensitive element(s) shall not be closer than 15 mm of the detector.

4.2

Plastic, if used, shall not start softening, deforming or melting at a temperature lower than 95°C

5. PERFORMANCE TEST AND CRITERIA FOR CONFORMITY

5.1

A sample of required number of detectors (see Tables 1 and 2) of each design selected randomly from production of not less than 200 detectors, shall be used for testing and shall be numbered. The test (one or more) shall be carried out in the order given in test schedule by the methods mentioned in Tables 1 and 2 and shall conform to the requirements given in 5.2 to 5.9. The detectors shall pass all the tests. All the tests are type tests which cover the production up to 10 000 numbers.

5.2

Directional Dependence and Response Time—Detector number mentioned in Table 1 or 2 (as applicable) shall be tested for these properties according to the method given in Appendix A and shall conform to the response time requirements for the three grades as given in Table 3 and in 5.2.1 (as applicable) in all orientations.

5.2.1

In case of ‘rate of temperature rise-cum-fixed temperature’ type detectors, the following requirement shall also apply additionally.

5.2.1.1

At rates of rise of air temperature less than l°C/min, the detector when tested according to the method given in Appendix A, shall be required to operate at an air temperature of not less than 58°C, and for Grades 1, 2 and 3 at not more than 65, 73 and 81°C, respectively.

5.3

Vibration—The detectors (see Table 1 or 2 as applicable for numbering and rate of temperature rise) shall be tested in the manner described in Appendix B and shall comply with its requirements.

5.4

Corrosion—The detectors (see Table 1 or 2 as applicable for numbering and rate of temperature rise) shall be tested in the manner described in Appendix C. They shall be deemed to comply with the test if:

1. For Four Days Corrosion—The response time of each detector remains within the

TABLE 1 TESTING SCHEME FOR RESETTABLE DETECTORS (Clauses 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 5.10, 5.11, A-3.1, B-1.1 and D-1.1)
Test Procedure		Detector Number										Rate of Rise (°C/min)							Remarks
Clause	Test	1	2	3	4	5	6	7	8	9	10	1	3	5	10	20	30	0.2
5.2, A-2	Directional dependence	1													x				8 orientations Two tests at each rate : one with most favourable orientation, other with least favourable orientation. With least favourable orientation
5.2, A-3	Time of response	1	2								x x	x x	x x	x	x x	x x	0* 0*
5.2. A-3	Response before test			3	4	5	6	7	8	9	10		x			x
5.3	Vibration			3	4
5.4	Corrosion, 4 days Corrosion, 16 days Corrosion, Salt spray				4			7	8	9	10
5.5	Shock					5	6
5.6	Low temperature	1	2												x
5.7	High temperature		2											x		x
5.8	Supply voltage variation		2
5.9	Insulation resistance	1																	Tests at both rates at upper and lower limits of supply voltage Measurement of resistance only With     least    favourable orientation
5.10	Humidity	1
5.11	Ageing (applicable to fusible link type only)	1											x
A-3	Response after test	1		3		5		7	8	9	10			x
			2		4		6		8		10
*Only for dercctors subject to testing under 5.2.1 and 5.2.2.

2.  

TABLE 2 TESTING SCHEME FOR NON-RESETTABLE DETECTORS (Each detector or element for one of the test only) (Clauses 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 5.10, 5.11, A-3.1, B-1.1 and D-1.1)
Test Procedure		Element or Detectors Number	Rate of Rise (°C/Min)							Remarks
Clause	Test	1 to 8	1	3	5	10	20	30	<0.2
5.2, A-2	Directional dependence	1 to 8				x				8 orientations
5.2, A-3	Time of response	9 to 22 23 to 36	x x	x     x	x x	x x	x x	x x	0* 0*	Two tests at each rate : one with most favourable orientation, other with least favourable orientation
5.3	Vibration	37 to 38
5.4	Corrosion, 4 days Corrosion, 16 days Corrosion, Salt spray	39 to 40 41 to 42          38
5.5	Shock	43 to 44
5.6	Low temperature	45 to 46
5.7	High temperature	47			x
5.8	Supply voltage variation	48 to 51		x		x
5.9	Insulation resistance	52								Measurement of resistance only
5.10	Humidity	53		x
5.11	Ageing (applicable to fusible link detectors only)	54		x
A-3	Response after test	37, 39, 41, 43, 45 38, 40, 42, 44, 46		x x						With least favourable orientation
*Only for detectors subject to testing under 5.2.1 and 5.2.2.

3.  

TABLE 3 ACCEPTANCE LIMITS FOR RESPONSE TIME (Clause 5.2)
Rate of Rise of Air Temperature	Lower Limit of Response Time for All Response Grades		Upper Limit of Response Time for
			Response Grade 1		Response Grade 2		Response Grade 3
D°C/min	min	s	min	s	min	s	min	s
(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
1	30	0	37	20	45	40	54	0
3	08	13	12	40	15	40	18	40
5	04	09	7	44	9	40	11	36
10		30	4	02	5	10	6	18
20		22-5	2	11	2	55	3	37
30		15	1	34	2	8	2	42

d.  limits of its grade with an additional tolerance of ± 15 percent or 10 whichever is greater.

5. For Sixteen Days Corrosion—(Sulphur dioxide and salt spray)
1. Each detector gives an immediate continuous fault signal on connection to its C & I equipment, or
2. Each detector gives an alarm signal in time which does not exceed the upper limits of response grade 3.

5.5

Shock—The detector (see Table 1 and 2, as applicable for number and rate of temperature rise) shall be tested in the manner described in Appendix D. They shall be deemed to comply with the test if:

1. no alarm is given when they are subjected to the specified shock; and
2. any change in response time of the detectors after the test when compared with the response time obtained before the test does not exceed 15 percent or 10 s, whichever is greater.

5.6

Low Temperature—Response time of detectors (see Table 1 or 2, as applicable for numbering) shall be put inside a suitable chamber/tunnel/enclosure and connected to its control and indicating equipment. Air temperature in the chamber shall then be reduced to a minimum of 0 ± 1°C at a rate not exceeding l°C/min. The detector shall be kept in the condition of minimum temperature for 1 h to allow its temperature to stabilize. After 1 h stabilization, the detector shall be taken out and kept at a temperature of 27 ± 3°C for 5 to 6 h and then response times measured (see Appendix A), one at 3°C/min rate of temperature rise and the other at 20°C/min rate of temperature rise using least favourable orientation. Detectors shall be deemed to comply with this test if:

1. no alarm is initiated during the test, and
2. any change in response time of the detectors measured after the test when compared with the response time obtained before the test does not exceed 15 percent or 10 s, whichever is greater.

5.7

High Temperature—The detector (see Table 1 or 2, as applicable for numbering/rate of temperature rise) shall be mounted in the tunnel in its normal operating condition with its normal fastenings. Keeping the detector energized and disconnected from control and indicating equipment, temperature of air flow in the tunnel shall be raised to 50°C at a rate not exceeding 1°C/min. The temperature at this level shall be maintained for 1 h. The detector shall then be energized and the response time shall be measured (see Appendix A) at 5°C/min rate of temperature rise using the least favourable orientation. The detector shall respond within a time not exceeding 11 min and 36 s for Grade 3, 9 min and 40 s for Grade 2, and 7 min and 44 s for Grade 1.

5.8

Supply Voltage Variation—The detector (see Table 1 or 2, as applicable for numbering/rate of temperature rise) shall be tested and response times measured as described in Appendix E. They shall be deemed to comply with this test if, as a result of supply variation, when compared with the response time obtained before and after the test does not exceed 15 percent or 10 s, whichever is greater and shall not give false alarm during the test.

5.9

Insulation Resistance—The detector (see Table 1 or 2, as applicable) shall be mounted in its normal operating condition with its normal area fastening on a metal plate of at least 2 mm thickness and having surface area at least 5 times the mounting surface of the detector. With the plate shorted to ground terminal of the voltage source, voltage shall be applied between the plate and the terminals of the detector which are inter-connected. In 5 s, voltage shall be applied to a maximum of 500± 10 volts DC. The maximum voltage shall remain applied for one minute. Insulation resistance shall then be determined. Thereafter, it shall be subjected to a temperature of 43 ± 2°C and relative humidity of 90 ± 3 percent for 10 days. After conditioning, the detector shall be kept at room condition for one hour. The insulation resistance shall be measured again. The detector shall be deemed to comply with the test if the resistance in first measurement before the exposure is not less than 10 M? and in second measurement after the exposure is not less than 1 MΩ, and the detector shall not give a false alarm during the test.

5.10

Humidity—The detector (see Table 1 or 2, as applicable) shall be kept inside a suitable humidity climatic chamber and connected to its control and indicating equipment. Following climatic conditions shall be created inside the test chambers:

Temperature	:	30 ± 2°C
RH	:	80 ± 5 percent
Duration of exposure	:	7 days

The detector shall be transferred to tunnel within 1 hour of removal from the chamber and its response time measured according to Appendix A. The time measured after the exposure and before shall not differ by a factor greater than 16 and the detector shall not give false alarm during the test.

5.11

Ageing (Applicable to Fusible Alloy Link Type)—The detector (see Table 1 or 2, as applicable) shall be placed in a suitable temperature oven and exposed for a period of 90 days to an ambient air temperature which is 15°C below the rated operating temperature of the detector but not less than 50°C. Following the exposure, the detector shall be allowed to cool for not less than 5 hours. After cooling, the detector operating temperature shall be ascertained according to Appendix A. The detector shall operate within a temperature rangeT ± (0.035 T + 062) °C.

Note—T°C is rated operating temperature.

6. INFORMATION

6.1

Sufficient information shall be given with the detectors to facilitate their correct application. Such information shall include broad details of general and technical features of the detector, correct monitoring position, reference to owners manual, operation of test feature (if provided), maintenance instructions, required electrical interface with the control and indicating equipment which may take the form either of the values of current, voltage, etc, and their allowable tolerances or a restriction of the detector to be used only in conjunction with specified control and indicating equipment, etc.

7. MARKING

7.1

Each detector shall be legibly and indelibly marked with the following:

1. Manufacturers name or trade-mark;
2. Type and description of detector and number;
3. Year of manufacture;
4. Grading of detector which shall be clearly indicated either by the colours as mentioned below, or by other suitable means;
1. Grade 1 : green
2. Grade 2 : yellow
3. Grade 3 : red; and
5. Whether provided with fusible link.

7.2

Each detector may also be marked with the Standard Mark.

Note—The use of the Standard Mark is governed by the provisions of the Bureau of Indian Standards Act 1986 and the Rules and Regulations made thereunder. The Standard Mark on products covered by an Indian Standard conveys the assurance that they have been produced to comply with the requirements of that standard under a well defined system of inspection, testing and quality control which is devised and supervised by BIS and operated by the producer. Standard marked products are also continuously checked by BIS for conformity to that standard as a further safeguard. Details of conditions under which a licence for the use of the Standard Mark may be granted to manufacturers or producers may be obtained from the Bureau of Indian Standards.

APPENDIX A
METHOD OF TEST FOR TIME OF RESPONSE AND DIRECTIONAL DEPENDENCE (Clauses 5.2, 5.2. 1.1, 5.6, 5.7, 5.10, 5.11 and Tables 1 and 2)

A-1. APPARATUS

A-1.1

The response time and directional dependence shall be measured in a wind tunnel specified in Fig. 6 of IS : 9972–1981*. The air velocity in the tunnel shall be 0.8 ± 0.1 m/s and the air temperature shall be 28°C.

*Specification for automatic sprinkler heads.

A-1.2

The detector shall be mounted in its normal operating position on a board forming part of the ceiling of the working section of the tunnel so that it is symmetrically disposed with respect to the side walls of the tunnel, possibly in least favourable mounting position. The air temperature shall be measured by suitable thermocouple (copper-constantan wire not exceeding 025 mm in diameter, junction consisting of a half twist with tightly tinned joint). The temperature measuring device shall be approximate, at the same distance from the ceiling of the wind tunnel as the sensitive element of the detector and approximately 230 mm from the sensitive element against the flow of air in a horizontal direction. Before the test, the temperature of the air stream and the detector shall stabilized at 28°C. The temperature control of the tunnel shall be such that the temperature may be varied at 1, 3, 5, 10, 20 and 30°C/min with air temperature within the tunnel being at all times within ± 3°C of that required by the set rate of change of temperature, and also such that the temperature can be raised from 52°C at a rate not exceeding 0.2°C/min to a temperature of 83°C.

A-2. DETERMINATION OF DIRECTIONAL DEPENDENCE

A-2.1

The detector(s) shall be connected to its control and indicating equipment and tested in an air stream having a constant mass flow, equivalent to a velocity of 08 ± 0.1 m/s at 28°C and with a uniform rate of rise of air temperature of 10°C/min. Eight such tests shall be made, the detector being rotated about a vertical axis by 45° between successive tests so that the tests are made with eight different orientations.

A-2.2

The least favourable and most favourable orientations giving the greatest and the least time delays, respectively, between the initiation of the temperature rise and the operation of the detector shall be recorded.

A-3. TIME OF RESPONSE MEASUREMENT

A-3.1

The detectors, the response times of which are to be measured as mentioned in Tables 1 and 2, shall be connected to the indicating equipment and shall be tested in an air stream having a constant mass flow equivalent to a velocity of 0.8 ± 0.1 m/s at 28°C and having uniform rates of rise of air temperature 1, 3, 5, 10, 20 and 30°C/min (as applicable). The scheme of tests for various detectors is given in Tables 1 and 2. The time interval between the initiation of temperature rise and the operation of detector shall be recorded to an accuracy of 0.5 s and shall be designated as the time of response.

A-4. FIXED TEMPERATURE OPERATION

A-4.1

Two detectors shall be tested as in A-3 with a rate of rise of air temperature not exceeding l°C/min until the air temperature reaches 50°C and thereafter with a rate of rise of air temperature not exceeding 0.2°C/min. One of the detectors shall be in less favourable and the other in most favourable orientation. The air temperature at the operation of the detectors shall be recorded.

APPENDIX B
VIBRATION TEST (Clause 5.3 and Tables 1 and 2)

B-1. PROCEDURE

B-1.1

The detector (see Table 1 or 2, as applicable for numbering/rate of temperature rise), connected to its indicating equipment, shall be mounted in its correct operating position and response time (see Appendix A) shall be noted and then the detector shall be put on a vibration table. The test shall then be subjected to a vertical vibration of amplitude 0.1 mm for a period of 5 minutes at each of the following frequencies:

10, 15, 20, 25, 30, 35, 40, 45, and 50 c/s.

B-1.2

The operation of the detector or resonance of any component shall be noted. If resonance occurs, the detector shall be vibrated at the resonant frequency for a period of one hour. If no resonance occurs, the detector shall be vibrated at 50 c/s for one hour.

B-1.3

No fault or alarm warning shall be indicated and no mechanical defect (including the breakage/displacement of sensitivity seal, if provided) shall be visible during or after the tests as in B-1.1 and B-1.2. The time of response of two detectors shall be determined after the test. The change in response, before and after the test shall not exceed 15 percent or 10 s, whichever is greater.

APPENDIX C
CORROSION TEST (Clause 5.4 and Tables 1 and 2)

C-1. PROCEDURE

C-1.1

At least 15 cm of connection wires/cables prescribed by the manufacturer shall be connected to each detector or socket. When specific types of wires/cables are not prescribed for connection, a 138 mm diameter (or nearest equivalent) single copper wire, untinned, shall be used for connection leads in this test. The lowest point of the detector shall be between 25 and 50 mm above the liquid surface. A guard shall be provided to prevent drops of liquid from falling into the upper surface of the detector.

C-1.2

The detector (see Table 1 or 2 as applicable for numbering) shall be subjected to a corrosion atmosphere of Sulphur dioxide saturated with water vapor and maintained at temperature of 45 ± 3°C. The apparatus shall consist of a 5 litre glass beaker fitted with a cover, an electric heater, and a thermostat which can be set at 45 ± 3°C and copper tubing for flow of cool water round the beaker.

The thermostat shall be placed 140 mm above the bottom of the beaker. A hole is to be provided in the lid for the insertion of the thermometer. The corrosion atmosphere shall be produced by placing in beaker, a solution containing 20 g of sodium thiosulphate (Na₂S₂O₈.5H₂O) in 500 ml of water. The detector shall then be suspended in beaker and 10 ml of acid consisting of 156 ml of normal sulphuric acid (H₂SO₄) per litre of aqueous solution shall be added twice daily. During the test, the temperature near the detector shall be maintained at 45 ± 3°C by the heater and the thermostat and water flow in cooling coil shall be so regulated that the temperature at the outlet does not exceed 30°C. Where a test is intended to last for more than 8 days, the detector shall be removed after 8 days and the beaker emptied and cleared. A further 20 g of sodium thiosulphate in 500 ml of water shall be put in the beaker, the detector replaced and the corrosive atmosphere produced and maintained as before for a period of 8 days again.

C-1.2.1

The first pair of detectors shall be mounted in the beaker and exposed to corrosive atmosphere for a period of four days. Sixteen days exposure shall be given to the third detector. After prescribed exposures, the detectors shall be removed and allowed to dry for seven days, in normal room environment without disturbing the connections and the response time of detectors shall be measured as in Appendix A.

C-1.3

Salt Droplet Test—This test shall be conducted on the fourth detector. The detector shall be suspended with its lower edge 5 to 75 cm above the surface of water in a large dish and the whole shall be enclosed by a box-like cover. Once daily for a total period of 16 days the detector shall be removed, sprayed over its whole surface by a spray of sea water of the following composition and replaced under this cover;

Sodium chloride, g/l	23
Sodium sulphate, g/l	8.9
Magnesium chloride, g/l	9.8
Calcium chloride, g/l	1.2

The temperature throughout the test shall be maintained at 27 ± 2°C. After 16 days, the detector shall be removed and allowed to dry. It shall then be connected to its normal indicating equipment using the corroded lead and the response time shall be measured as in Appendix A.

APPENDIX D
SHOCK TEST (Clause 5.5)

D-1. PROCEDURE

D-1.1

The response time of the detector (see Table 1 or 2, as applicable for numbering/rate of temperature rise for test) shall be determined. A detector incorporating electrical contacts shall be mounted on a piece of 10 × 5 cm hardwood resting on edge on solid supports spaced 1 m apart. The test shall be made with the detector in the following two positions:

1. At the midpoint on the horizontal under side, and
2. At the midpoint on the vertical side.

D-1.2

A metal block of 35 kg mass shall be dropped on to the midpoint of the 10 x 5 cm timber from a height of 30 cm above the top horizontal surface of the timber. The detector shall be connected in circuit corresponding to its normal operation during the test and shall not operate as a result of shock.

D-1.3

After the test, the time of response of the detectors shall be determined (see Appendix A) :

APPENDIX E
SUPPLY VOLTAGE VARIATION TEST (Clause 5.8)

E-1. PROCEDURE

E-1.1

When upper and lower limits of supply voltage are prescribed, detector(s) shall be tested at both the limits. At upper limit, two tests shall be carried out and similarly two tests shall be conducted at the lower limit. When one nominal value of supply voltage is prescribed, two tests shall be carried out with voltage to control and indicating equipment reduced as 85 percent of nominal value (to be treated to lower limit) and further two tests with voltage increased to 110 percent of the nominal value and the response time measured (see Appendix A). In each pair of tests, one test shall consist of the measurement of response time with a rate of rise of 3°C/min and the other with a rate of rise of 20°C/min. The response times shall be recorded. For resettable detectors, the same detector shall be used for all the tests of E-1.1. For non-resettable detectors, a separate detector or detector element shall be used for each of the tests of E-1.1.

NFPA 72 - Heat Detection

Heat detectors work by detecting a temperature change or a high temperature limit. There are several types of heat detectors, including fixed-temperature, elevation rate, and combination detectors that use both types of sensing.

👉🏻Fixed-temperature heat detectors operate by activating an alarm when a predetermined temperature limit is reached. For example, a heat detector can be configured to trigger an alarm when the temperature in a room reaches 57 °C (135 °F).

👉🏻Rate of increase heat detectors operate by detecting rapid temperature increases. These detectors will activate an alarm if the temperature rises too quickly, even if the temperature does not reach a predetermined limit. For example, a rate of increase detector can be activated if the temperature in a room rises by 15 °F (8 °C) in a minute.

👉🏻Combined heat detectors use fixed temperature and rate of rise sensors to provide more comprehensive fire detection. These detectors are often used in areas where fires can develop rapidly, such as kitchens and boiler rooms.

Heat detectors use different technologies to detect temperature, including thermocouples, thermistors, and infrared sensors.

👉🏻Thermocouples and thermistors work by measuring changes in electrical resistance that occur as the temperature changes. Infrared sensors detect changes in infrared radiation emitted by objects as they heat.

Once a heat detector detects a temperature change or a high temperature threshold, it will activate an alarm or alert system, such as a strobe light or voice alarm, to alert occupants of the potential fire risk.