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Ordinance for Technical Specifications pertaining to Water Flow Detecting Devices(Ordinance of the Ministry of Home Affairs No. 2 of January 18, 1983)
Latest update: Ordinance of the Ministry of Home Affairs No. 44 of September 14, 2000
In accordance with the provision of Article 21-2(2) of the Fire Service Act (Act No. 186 of 1948), theOrdinance for Complete Revision of Technical Specifications pertaining to Water Flow Detecting Devices(Ordinance of the Ministry of Home Affairs No. 18 of 1975) shall be specified as follows.
PurportArticle 1

This Ordinance covers the technical specifications applicable to water flow detecting devices foruse in sprinkler systems, water spray extinguishing systems, or foam extinguishing systems (hereinafterreferred to as “water flow detecting devices”).
Definitions
Article 2

In this Ordinance, the meanings of the terms listed in the following items shall be as prescribed

respectively in those items.
(i) Water flow detecting device: The wet, dry, and pre-action water flow detecting devices that
automatically detect the water flow in the devices to generate signals or alarms.
(ii) Wet water flow detecting device: The device where the primary system (refers to the inflow side up to
the valve body of the device; the same shall apply hereinafter) and the secondary system (refers to theoutflow side from the valve body of the device; the same shall apply hereinafter) are filled with pressurizedwater or pressurized foam solution (hereinafter referred to as “pressurized water, etc.”) and, when theautomatic closed sprinkler head or deluge valve (referred to as “automatic closed sprinkler head, etc.” in thenext item) is opened, opens the valve body as a result of pressure drop in the secondary system so thatpressurized water, etc. will be discharged to the secondary system.
(iii) Dry water flow detecting device: The device where the primary system is filled with pressurized waterand the secondary system is filled with pressurized air and, when the automatic closed sprinkler head, etc.
is opened, opens the valve body as a result of pressure drop in the secondary system so that pressurizedwater, etc. will be discharged to the secondary system.
(iv) Pre-action water flow detecting device: The device where the primary system is filled with pressurizedwater and the secondary system is filled with air and, when the detector, fire detection head, or other fire
detecting equipment of the fire detection and fire alarm system (hereinafter referred to as “detection unit”)
is operated, opens the valve body so that pressurized water, etc. will be discharged to the secondary system.
(v) Service pressure range: The primary system’s pressure range within which the water flow detecting
device does not generate functional degradation.
(vi) Design pressure: The secondary system pressure setting provided within the service pressure range tokeep the balance with the primary system pressure on the water flow detecting device that requires thepressure setting in the secondary system.

Structure
Article 3

The wet water flow detecting device shall meet the following structural requirements.

(i) The wet water flow detecting device that actuates the water supply system shall have the same structuraldesign as the check valve.
(ii) The wet water flow detecting device shall not generate functional degradation due to deposits.
(iii) The pipe joint shall be designed to permit easy connection with piping.
(iv) The portion where pressurized water, etc. flows shall be finished smoothly.
(v) The body and components of the device shall permit easy maintenance, inspection, and replacement.
(vi) The valve seat surface shall be free from harmful imperfections that will cause functional degradation.
(vii) Effective drip-proof measures shall be arranged for switches.
(viii) The sensitivity adjustment device shall not be exposed to the external environment.
(2) The dry water flow detecting device shall meet the following structural requirements in addition to thoseprescribed in the items in the preceding paragraph (except for Item (i)).
(i) The dry water flow detecting device shall be equipped with the unit that protects the valve body once
opened from reclosing due to water hammer, back flow, or other unpreferable phenomena except for thecase that the operation pressure ratio (refers to the value calculated by dividing the primary system pressure,which is observed on the valve body immediately before the opening action, by the secondary systempressure) is not more than 1.5.
(ii) The dry water flow detecting device shall be capable of replenishing the pressurized air to the secondary
system.
(iii) The dry water flow detecting device shall be equipped with the unit capable of checking signal or alarm
generation function without opening the valve body.
(iv) The dry water flow detecting device that has an intermediate chamber separating the primary systemfrom the secondary systems shall be equipped with the unit that automatically drains water collected in thechamber to the external environment.
(v) The dry water flow detecting device that requires standby water in the secondary system shall beequipped with the unit that ensures the necessary level of the standby water.
(vi) The dry water flow detecting device that does not require standby water in the secondary system shallbe equipped with the unit that drains water collected in that system to the external environment.
(3) The pre-action water flow detecting device shall meet the structural requirements prescribed in the items
in Paragraph (1) (except for Item (i)) and Paragraph 2 (except for Item (ii)). In addition, the water flow
detecting device that requires the pressure setting in the secondary system shall be capable of replenishing
the pressurized air.
Material
Article 4

The water flow detecting device shall meet the following material requirements.

(i) Major portions of the water flow detecting device shall be made of the material conforming to JIS (refers
to the Japanese Industrial Standards prescribed in Article 17(1) of the Industrial Standardization Law (ActNo. 185 of 1949); hereinafter the same shall apply in this item) G 5501, G 5151, H 5120, or H 5121, or thematerial having the mechanical strength and corrosion resistance equal to or higher than those of these JISmaterials.

(ii) For the portions sensitive to rust, an effective rust preventive treatment shall be provided.
(iii) Rubbers, synthetic resins, and other sensitive components used in the water flow detecting device shallendure property alteration prolongedly.
Maximum service pressure range
Article 5

The maximum service pressure range of the water flow detecting device shall stay within therange prescribed in the following table in accordance with the nominal designation specified in that table.
Nominal designation /// Pressure, MPa
10K /// 1.0 to 1.4
16K /// 1.6 to 2.2
Withstanding pressure
Article 6

When the pressure prescribed in the following table and determined in accordance with thenominal designation specified in that table is applied to the wet water flow detecting device for 2 min, its
valve box shall not generate water leak, deformation, damage, or rupture.
Nominal designation /// Pressure, MPa
10K /// 2.0
16K /// 3.2(2) When the design pressure (equal to the maximum service pressure) multiplied by 3 or the pressure
shown in the table of the preceding paragraph and determined in accordance with the nominal designation
specified in that table, whichever is larger, is applied to the dry and pre-action water flow detecting devices
for 2 min, the valve bodies of these devices shall not generate water leak, deformation, damage, or rapture.
(3) When the secondary system design pressure associated with the primary system service pressure isapplied to the secondary system and the primary system service pressure multiplied by 1.1 is applied to theprimary system for 2 min, the valve seats of the dry and pre-action water flow detecting devices shall notgenerate water leak.
Function
Article 7

Wet water flow detecting devices shall meet the following functional requirements.

(i) Depending on the pressure within the service pressure range and the detection flow constant (refers to
the flow detected as water flow phenomenon to control the generation of signals or alarms; the same shallapply hereinafter), the wet water flow detecting device shall continuously generate signals or alarms within
1 min from the initiation of water flow at the rate specified below and stop these signals or alarms whenwater is no longer delivered.
(a) When the detection flow constant is 80 and 50, the flow rate shall be obtained from the following
equation. If the pressure is 0.5 MPa or less, the flow rate shall be 80 L/min for the detection flow constantof 80 and 50 L/min for the constant of 50.
Q = 0.75 × K√10P

where,
Q: Flow rate, L/min
K: Detection flow constant
P: Pressure, MPa(b) When the detection flow constant is 60, the flow rate shall be 60 L/min at the pressure within the servicepressure range.
(ii) When pressurized water, etc. is delivered at 4.5 m/s, the wet water flow detecting device shallcontinuously generate signals or alarms. The device shall stop these signals or alarms when water is nolonger delivered.
(iii) Even when the water flow is initiated at the no-operation flow rate at the minimum service pressure(refers to the predetermined maximum flow rate that is observed in the wet water flow detecting device andwill not generate signals or alarms; the same shall apply hereinafter), the device shall not generate signals
or alarms.
(iv) When an instantaneous pressure fluctuation occurs in the primary system, the wet water flow detecting
device shall not continuously generate signals or alarms.
(2) The dry water flow detecting device shall meet the following functional requirements in addition to
those prescribed in Paragraph (1)(iv).
(i) When the pressurized air is released from the automatic closed sprinkler head characterized by thenominal designation of 15, the valve body of the dry water flow detecting device shall be opened within 30
s under the secondary system pipe volume prescribed in the following table and determined in accordancewith the inside diameter specified in that table, and the device shall continuously generate signals or alarms
within 1 min.
Inside diameter, mm /// Secondary system pipe volume, L
50 /// 70
65/// 200
80 /// 400
100 /// 750
125 /// 1200
150 /// 2800
200 /// 2800
(ii) When pressurized water, etc. is delivered at 4.5 m/s, the dry water flow detecting device shallcontinuously generate signals or alarms.
(3) The pre-action water flow detecting device shall meet the following functional requirements in addition
to those prescribed in Paragraphs (1)(iv) and (2)(ii).
(i) When the detection unit is operated, the valve body of the pre-action water flow detecting device shallbe opened within 30 s under the secondary system pipe volume prescribed in the table of Paragraph (2)(i)and determined in accordance with the inside diameter specified in that table, and the device shallcontinuously generate signals or alarms within 1 min.
(ii) The pre-action water flow detecting device that recloses the valve body upon shutdown of the detection

unit shall stop signals or alarms when this unit no longer works.
Durability
Article 8

When pressurized water, etc. is delivered at 4.5 m/s for 30 min, the water flow detecting device

shall not generate functional degradation.
(2) When the dry and pre-action water flow detecting devices are operated at the maximum service pressure
under the secondary system pipe volume prescribed in the table of Article 7(2)(i) and determined inaccordance with the inside diameter specified in that table, and then the primary system is controlled to theatmospheric pressure, the devices shall not generate functional degradation.
Functions of components
Article 9 When the pressure switch is subjected the 2000-cycle test, it shall not generate functional
degradation. One cycle consists of the pressure fluctuation where the pressure is changed between 0 MPa
and maximum service pressure (if the highest pressure applied to the switch is lower than the maximum
service pressure, that highest pressure shall be used) at the rated voltage and current with 1 s of energizationtime.
(2) The water motor gong shall meet the following requirements.
(i) When the gong is continuously operated for 3 h, it shall not generate functional degradation.
(ii) The gong shall be capable of keeping the sound volume of not less than 90 dB at the place 3 m apartfrom it.
Pressure loss
Article 10 When water is delivered at the rate prescribed in the following table and determined inaccordance with the inside diameter specified in that table, the pressure loss of the wet water flow detecting
device shall not exceed 0.05 MPa.
Inside diameter, mm /// Flow rate, L/min
25 /// 130
32 /// 200
40 /// 350
50 /// 550
65 /// 900
80 /// 1350
100 /// 2100
125 /// 3300
150 /// 4800
200 /// 8500
Indication
Article 11 The information specified in the following items shall be indicated on all water flow detecting
devices at easily observable place in such the manner that the subject information may not be readilyerased.

(i) Classification of the device: Wet, dry, or pre-action(ii) Type and model code(iii) Manufacturer’s name or trademark(iv) Year of manufacture(v) Manufacturing number(vi) Inside diameter, nominal designation, and service pressure range(vii) Pressure loss expressed in equivalent straight pipe length(viii) Design pressure for the water flow detecting device that requires the pressure setting in the secondary
system(ix) No-operation flow rate at the minimum service pressure for the wet water flow detecting device(x) Arrow mark indicating the direction of flow(xi) Direction of installation(xii) Combination of components(xiii) Term “50” for the water flow detecting device having detection the flow constant of 50 or “60” for thedevice having the flow constant of 60
Exemption from standards
Article 12

When the Minister of Internal Affairs and Communications recognizes that water flow

detecting devices newly created as a result of technology development activities have the performanceequivalent to or higher than those conforming to the provisions prescribed in this Ordinance, judging fromtheir profiles, structures, materials, and performance, the technical standards specified by the Minister ofInternal Affairs and Communications shall apply to these new developments notwithstanding the provisionsof this Ordinance.
Supplementary Provisions(1) This Ordinance shall come into effect as of April 1, 1983.
(2) For tests pertaining to water flow detecting devices whose application for test has been already made tohave the fire extinguishing equipment apparatus tested by the Japan Fire Equipment Inspection Instituteat the time of enforcement of this Ordinance, the provisions then in force shall remain applicable.
Supplementary Provisions (Ordinance of the Ministry of Home Affairs No. 7 of March 18, 1987)
This Ordinance shall come into effect as of the day of promulgation.
Supplementary Provisions (Ordinance of the Ministry of Home Affairs No. 30 of September 13, 1995)(1) This Ordinance shall come into effect as of October 1, 1995.
(2) For water flow detecting devices that have already got model approvals at the time of enforcement of
this Ordinance, their model approvals shall be deemed as those provided in accordance with the standards
prescribed in the amended Ordinance for Technical Specifications pertaining to Water Flow Detecting
Devices.
Supplementary Provisions (Ordinance of the Ministry of Home Affairs No. 37 of September 28,1998)-ExcerptEffective date
Article 1

This Ordinance shall come into effect as of October 1, 1999.

Transitional measures
Article 2

For tests pertaining to fire extinguishers, fire extinguishing agents, automatic closed sprinkler

heads, fire hoses, deluge valves, foam concentrates, detectors and manual call points, water flow detecting
devices, plug-in couplings, and screw couplings whose application for test has been already made to havethe target equipment tested by the Japan Fire Equipment Inspection Institute at the time of enforcementof this Ordinance, the provisions then in force shall remain applicable.
(2) For fire extinguishers that have already got model approvals and fire extinguishers that have got model
approvals based on the results from the tests identified by the prescription “provisions then in force shallremain applicable” as described in the preceding paragraph at the time of enforcement of this Ordinance,
their model approvals shall be deemed as those provided in accordance with the standards prescribed in the
Ordinance for Technical Specifications pertaining to Fire Extinguishers amended according to theprovisions of Article 1.
(3) For fire extinguishing agents that have already got model approvals and fire extinguishing agents thathave got model approvals based on the results from the tests identified by the prescription “provisions thenin force shall remain applicable” as described in Paragraph (1) at the time of enforcement of this Ordinance,
their model approvals shall be deemed as those provided in accordance with the standards prescribed in the
Ordinance for Technical Specifications pertaining to Fire Extinguishing Agents amended according to theprovisions of Article 2.
(4) For automatic closed sprinkler heads that have already got model approvals and automatic closed
sprinkler heads that have got model approvals based on the results from the tests identified by theprescription “provisions then in force shall remain applicable” as described in Paragraph (1) at the time ofenforcement of this Ordinance, their model approvals shall be deemed as those provided in accordance withthe standards prescribed in the Ordinance for Technical Specifications pertaining to Automatic Closed
Sprinkler Heads amended according to the provisions of Article 3.
(5) For fire hoses that have already got model approvals and fire hoses that have got model approvals basedon the results from the tests identified by the prescription “provisions then in force shall remain applicable”
as described in Paragraph (1) at the time of enforcement of this Ordinance, their model approvals shall bedeemed as those provided in accordance with the standards prescribed in the Ordinance for Technical
Specifications pertaining to Fire Hoses amended according to the provisions of Article 4.
(6) For deluge valves that have already got model approvals and deluge valves that have got model
approvals based on the results from the tests identified by the prescription “provisions then in force shallremain applicable” as described in Paragraph (1) at the time of enforcement of this Ordinance, their model
approvals shall be deemed as those provided in accordance with the standards prescribed in the Ordinancefor Technical Specifications pertaining to Deluge Valves amended according to the provisions of Article 5.
(7) For foam concentrates that have already got model approvals and foam concentrates that have got
model approvals based on the results from the tests identified by the prescription “provisions then in force
shall remain applicable” as described in Paragraph (1) at the time of enforcement of this Ordinance, theirmodel approvals shall be deemed as those provided in accordance with the standards prescribed in theOrdinance for Technical Specifications pertaining to Foam Concentrates amended according to theprovisions of Article 6.
(8) For detectors and manual call points that have already got model approvals and detectors and manual
call points that have got model approvals based on the results from the tests identified by the prescription“provisions then in force shall remain applicable” as described in Paragraph (1) at the time of enforcementof this Ordinance, their model approvals shall be deemed as those provided in accordance with thestandards prescribed in the Ordinance for Technical Specifications pertaining to Detectors and Manual Call
Points of Fire Detection and Fire Alarm Systems amended according to the provisions of Article 7.
(9) For water flow detecting devices that have already got model approvals and water flow detecting
devices that have got model approvals based on the results from the tests identified by the prescription“provisions then in force shall remain applicable” as described in Paragraph (1) at the time of enforcementof this Ordinance, their model approvals shall be deemed as those provided in accordance with thestandards prescribed in the Ordinance for Technical Specifications pertaining to Water Flow Detecting
Devices amended according to the provisions of Article 8.
(10) For plug-in couplings that have already got model approvals and plug-in couplings that have got model
approvals based on the results from the tests identified by the prescription “provisions then in force shallremain applicable” as described in Paragraph (1) at the time of enforcement of this Ordinance, their model
approvals shall be deemed as those provided in accordance with the standards prescribed in the Ordinancefor Technical Specifications pertaining to Plug-in Couplings used for Fire Hoses amended according to theprovisions of Article 11.
(11) For screw couplings that have already got model approvals and screw couplings that have got model
approvals based on the results from the tests identified by the prescription “provisions then in force shallremain applicable” as described in Paragraph (1) at the time of enforcement of this Ordinance, their model
approvals shall be deemed as those provided in accordance with the standards prescribed in the Ordinancefor Technical Specifications pertaining to Screw Couplings used for Fire Hoses or Fire Suction Hoses
amended according to the provisions of Article 12.
(12) For power driven fire pumps that were notified to the Minister of Home Affairs in accordance with theprovision of Article 21-16-4(1) of the Fire Service Act (Act No. 186 of 1948) before the enforcement of thisOrdinance, they shall be deemed as those that conform to the standards prescribed in the Ordinance forTechnical Specifications pertaining to Power Driven Fire Pumps amended according to the provisions ofArticle 9.
(13) For fire suction hoses that were notified to the Minister of Home Affairs in accordance with theprovision of Article 21-16-4(1) of the Fire Service Act before the enforcement of this Ordinance, they shallbe deemed as those that conform to the standards prescribed in the Ordinance for Technical Specifications
pertaining to Fire Suction Hoses amended according to the provisions of Article 10.
Supplementary Provisions (Ordinance of the Ministry of Home Affairs No. 44 of September 14, 2000)
This Ordinance shall come into effect as of the effective date (January 6, 2001) of the Act for Partial
Revision of Cabinet Law (Act No. 88 of 1999).