2.2

Overview of the Risk Assessmentfor Residential Air-Conditioners
・JRAIA：Japan Refrigerating and Air-conditioning Industry associations
・Residential AC Risk Assessment SWG Chief investigator
Kenji Takaichi・Members
Madoka Ueno

Shigeharu TairaRyuichi Takatou

Toshiyuki Fuji

© 2013 MITSUBISHI HEAVY INDUSTRIES, LTD. All Rights Reserved.

Kouichi Yamaguchi
Hiroshi Makino

1． Agenda【1】Mildly flammable refrigerant risk assessment andthe tolerance level for residential air-conditioners【2】Study of mildly flammable refrigerant flammability【3】Risk assessment result by fault tree analysis【4】Risk assessment of Multi-split type air conditioner
for residential type【5】Conclusion© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

12． Tolerance level of safety

Probability

ISO Guide 51

A zoneB zoneC zone

NITE：Home appliances tolerance level is required 1×10-8 per 1million in market
Tolerance level
Amount of residential AC in Japan is 100 millionUse
1× 10-10Service etc. 1×10-9
NITE：National Institute of Technology and Evaluation© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

2

3． Hazards of R32 and R1234yf

Hazards of R32＆ R1234yf

Pressure（50℃）

toxicity

R410A

3.07MPaR410A None

R32,ｙｆ

3.14MPa

R32,ｙｆ None

Flammability
R410A No

ChangePoint

R32,ｙｆ Mildly

yf:R1234yf

Ignition Source
R410A

None

R32,ｙｆ

Open flame

Diesel explosion

Contact flame

R410A YesR410A Generation hydrofluoric acid

R32,ｙｆ Yes

R32,ｙｆ Generation hydrofluoric acid・Flammability and ignition source are studied in changing to R32 and R1234yf
・Diesel explosion and contact flame study are performed universities and AIST don’t change© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

3

4． FTA indoor space assumption●Indoor space, the conditions of a simulation
Wall mounted air-conditioner

Flammable
area

Floor mounted air-conditioner© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

45． Flammable volume and time integration●Flammable Volume and Time Integration
The rate of flammable volume being in certain space and certain time range
R32

R1234yf

R290

1.1 Logistics

2.00 × 10-4

2.20 × 10-45.50 × 10

1

2.2 Installation

2.40 × 10-32.50 × 10-4

7.16 × 10

2

2.5 Mistakes

9.00 × 10-31.30 × 10-27.75 × 10

2.10 Refrigerant charge

9.97 × 10

13.70 × 10

2

8.51 × 10

3

3.1 Indoor unit operation

5.00 × 10-45.50 × 10-4

1.41 × 10

1

3.5 Indoor unit stop

2.40 × 10-22.50 × 10-2

7.16 × 10

3

4.1 Outdoor unit

9.00 × 10-21.30 × 10-1

7.76 × 10

5.1 Connecting pipe

9.97 × 10

23.70 × 10

3

8.51 × 10

7.8 Service/relief

9.07 × 10-31.30 × 10-27.75 × 10

8 Disposal

-2

-1
3

-2

Using similar situations and values© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

56． Study of ignition：AIST
Ignition test ofExtinction Diameter of Opening

the magnetic contactor

Fig.5 The magnetic contractor（CLK65)

Fig.6 Apparatus for extinction
diameter measurement.

Fig.7 d* vs. h for R-32
and HFC-254fb.

●Under 3mm of clearances in case cover⇒ mildly flammable refrigerant no flame
propagation through clearances●Diameter of opening(d) and distances(h)⇒ Estimating mildly flammable refrigerant flame
can extinction■Reference
Study on Minimum Ignition Energy of Mildly
Flammable Refrigerant、 2011

■Reference
THE INTERNATIONAL SYMPOSIUM on
NEW REFRIGERANTS and ENVIRONMENTALTECHNOLOGY 2012

© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

6

7． Study of flammabilityⅠ：TUSS
Evaluation of physical hazard
・Study of flammability with heating system,
mildly flammable refrigerant leakedby room air-conditioner■Reference
THE INTERNATIONAL SYMPOSIUM on
NEW REFRIGERANTS and ENVIRONMENTALTECHNOLOGY 2012

Room Air-conditioner

Refrigerant

DumperHeating system●No flame propagation across the whole space was observed© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

78． Study of flammabilityⅡ：TUSS

Evaluation of lighter
・The refrigerant concentration at a heightof 0.3 m was within ignitable range
by a spark from a piezo lighter.

■Reference
THE INTERNATIONAL SYMPOSIUM on
NEW REFRIGERANTS and ENVIRONMENTALTECHNOLOGY 2012

Solenoid valve
Pneumatic
cylinderPush rod

Result1000

Refrigerant
mixture

air

Flame

300

Lighter

R1234yf Flammable● Ignition was observed when the button was pushed● But flame propagation from the outlet of the lighter tothe surrounding n-butane/mildly flammable refrigerant mixture© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

89． Risk assessment●reexamination of ignition source●From study of R32⇒mildly flammable refrigerant in a room air-conditioner leaked in the space,but no flame propagation across the whole space⇒Ignition was observed at the outlet of piezo lighter,but no flame propagation of lighter to n-butane/mildly flammable refrigerant mixture⇒Under 3mm of clearances in case cover,mildly flammable refrigerant no flame propagation through clearances

R410

R32

Ignition source

R290（Propane）●FlameIgnition→
Rarely ignition（Welding torch,
Oil lighter, Candle）

No ignition●Electric spark

No ignition

Ignition→
Rarely ignition

Ignition●Static electricity

No ignition

Ignition→ No ignition

OccasionallyIgnition© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

Ignition910． FTA of indoor unit using （Reexamination）

・ＦＴＡ ignition probability＝（Existence of Ignition source）×（Existence of flammable volume）© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1011． FTA of life cycle stage（Reexamination）
室内での着火Disposal

HFC32 2.0E-14～3.7E-10
廃棄での着火Ignitionof disposal
HC290 5.9E-09～1.1E-04

室内での着火serving

Ignition at
HFC32 2.0E-14～3.7E-10
サービスでの着火Ignitionof serving
Driving
HC290 5.9E-09～1.1E-04
HFC32 4.6E-17～8.6E-13
HC290 1.3E-12～2.4E-08
室内での着火Outdoor

Ignition at
HFC32 2.0E-14～3.7E-10
Ignition of outdoor
HC290 5.9E-09～1.1E-04
Driving
可燃範囲内に室内機からのHFC32 4.6E-17～8.6E-13
着火源が存在する
可燃冷媒漏洩
HC290 1.3E-12～2.4E-08
HFC32 2.9E-09～4.3E-08
HC290 8.0E-05～1.2E-03

Ignition at
室内での着火Driving
HFC32 4.6E-17～8.6E-13
of indoor
HFC32 2.0E-14～3.7E-10
可燃範囲内に Ignition
室内機からのHC290 1.3E-12～2.4E-08
HC290 5.9E-09～1.1E-04
着火源が存在する
可燃冷媒漏洩

Indoor
機器据付け時

据付け時の着火

可燃範囲内にInstall（未対策ケース）

Ignition at

着火源が存在する
Ignition
Driving of install

HFC324.6E-17～8.6E-13
2.9E-09～4.3E-08
HFC32
HC2901.3E-12～2.4E-08
8.0E-05～1.2E-03
HC290

R290
R32

エアコン据付頻度
2.1

冷媒への着火8.0E-028.0E-02

HFC32 2.0E-14～3.7E-10
HC290 5.9E-09～1.1E-04
Indor

運転中

HFC32 1.6E-07～2.0E-04
HC290 1.6E-07～2.0E-04

可燃範囲内に HFC32 2.0E-14～3.7E-10
室内機からの着火源が存在する HC290 5.9E-09～1.1E-04
可燃冷媒漏洩

HFC32 0.1
HC290 0.1Indor

HFC32 1.4E-07～2.1E-06
HC290 4.1E-02～6.2E-01

HFC32 0.9
HC290 0.9

HFC32 2.0E-14～3.7E-10
室内機からのHC290
5.9E-09～1.1E-04
停止中
可燃冷媒漏洩
急速冷媒漏洩
HFC32 1.4E-07～2.1E-06
HFC32 1.6E-07～2.0E-04
HFC32 0.9
室内機からの発生頻度／ｙHC290 4.1E-02～6.2E-01
HC290 1.6E-07～2.0E-04
HC290 冷媒漏洩発生確率0.9

可燃範囲内に着火源が存在する

運転中

HFC32 1.6E-07～2.0E-04
HFC32 0.1
急速冷媒漏洩
HC290 1.6E-07～2.0E-04 室内機からのHC290 0.1
発生頻度／ｙ
冷媒漏洩発生確率

停止中

HFC32 1.6E-07～2.0E-04
HC290 1.6E-07～2.0E-04

急速冷媒漏洩
HFC32 1.6E-07～2.0E-04
HFC32 0.1
室内機からの
P１/２
２０１１．１２．７
発生頻度／ｙHC290 1.6E-07～2.0E-04
HC290
0.1
冷媒漏洩発生確率
可燃範囲内に室内機からのHFC32 4.0E-07～5.0E-04
HFC32 0.4
運転中
Indor
着火源が存在する
可燃冷媒漏洩
HC290 4.0E-07～5.0E-04
HC290 0.4

HFC32 2.9E-09～4.3E-08
HC290 8.0E-05～1.2E-03
室内機からの
R290
3.8.E-05～
3.9.E-05
可燃冷媒漏洩
R32
6.1.E-07～
1.3.E-06

微燃性冷媒安全検討WG（ミニスプリットリスクアセスメントSWG）

Indor

停止中 HFC32 4.0E-07～5.0E-04
HC290 4.0E-07～5.0E-04
HFC32 HFC32
1.4E-07～2.1E-06
HFC32
1.6E-07～2.0E-04
HFC32 0.9
2.0E-14～3.7E-10
急速冷媒漏洩
HC290 HC290
4.1E-02～6.2E-01
HC290 1.6E-07～2.0E-04 室内機からのHC290 0.9
5.9E-09～1.1E-04
発生頻度／ｙ
冷媒漏洩発生確率

パナソニック（株）

HFC32 0.4
HC290 0.4

HFC32 4.0E-07～5.0E-04
HFC32 時間・体積当たりの0.4
HFC32 可燃になる
4.0E-07～5.0E-04
HFC32 0.4
可燃になる
時間・体積当たりのHC290 4.0E-07～5.0E-04
HC290 0.4HC290
4.0E-07～5.0E-04
HC290 0.4空間体積と持続時間
着火源の存在確率
空間体積と持続時間
着火源の存在確率
急速冷媒漏洩
室内機からの min･m3
室内機からのmin/m3
min･m3
min/m3
可燃範囲内に可燃範囲内に室内機からの発生頻度／ｙ
冷媒漏洩発生確率
運転中 冷媒漏洩発生確率
停止中
着火源が存在する
可燃冷媒漏洩
着火源が存在する
可燃冷媒漏洩
HFC32 4.0E-07～5.0E-04
HFC32 0.4
HFC32 4.0E-07～5.0E-04
HFC32 0.4
R290 4.8E-04～ 4.8E-04
R290 2.0E-06～ 1.0E-05
HC290 4.0E-07～5.0E-04
HC290 4.0E-07～5.0E-04
HFC32 2.9E-09～4.3E-08
HFC32 1.6E-07～2.0E-04
HFC32
0.1
HFC32HFC32
HFC32
1.6E-07～2.0E-04
HFC32 0.9時間・体積当たりのR32
5.6E-06～ 5.6E-06～ 1.4E-07～2.1E-06
1.0E-05
HFC32 HC290
5.0E-040.4R32 2.0E-06
5.7E-06～8.6E-05
HFC32 2.4E-02 HC290 0.4 HFC32 5.7E-06～8.6E-05
可燃になる
時間・体積当たりの可燃になる
HC290 8.0E-05～1.2E-03 空間体積と持続時間
HC290 1.6E-07～2.0E-04
HC290
0.1
HC290HC290
4.1E-02～6.2E-01
HC290 1.6E-07～2.0E-04
HC290 0.9 HC290
HC290 1.4E+01
5.7E-06～8.6E-05 空間体積と持続時間
7.2E+03
HC290 5.7E-06～8.6E-05
着火源の存在確率
着火源の存在確率
min･m3
min/m3
min･m3
min/m3R290
R32

4.8.E-04
7.6.E-06～～

4.9.E-04
1.6.E-05

急速冷媒漏洩
室内機からの発生頻度／ｙ

作業者の喫煙以外による着火

作業者の喫煙による着火接続配管（壁面内）

着火源が
存在する

室外機

室内機

R290
R32

4.8E-04
5.6E-06

R290
R32

冷媒漏洩
発生確率

着火源が
存在する

R290
R32

1.3E-07
4.3E-13～～～ 6.2E-09
可燃になる～ 2.1E-14
空間体積と持続時間
急速冷媒漏洩
min･m3
発生頻度／ｙ4.1E-10
1.4E-15

冷媒漏洩発生確率（工事不良による漏洩）
2.4

5.8E-09
6.7E-10

R290
R32

可燃になる
空間体積と持続時間
min･m3R290
R32

7.2E+02
2.4E-03

HFC32 5.0E-04
HC290 1.4E+01

8.5E+03
1.0E+02

R290
R290

可燃範囲内
に着火源が存在する確率

1.0E-02
1.0E-02

R290
R290

可燃になる

1.9E-06
6.5E-12R290
R32

1.0E+00
1.0E+00

4.4E-07
5.1E-08～～

6.7E-06
7.7E-07

R290
R32

HFC32 4.0E-07～5.0E-04

HFC32 0.4HC290
4.0E-07～5.0E-04
HFC32
2.4E-02R290
1.7E-03～ 8.4E-03
1.7E-03～ 8.4E-03
HC290 R327.2E+03

HC290 0.4
HFC32 5.7E-06～8.6E-05
HC290 5.7E-06～8.6E-05

可燃冷媒が漏洩

1.3E-02
1.3E-02

HC290 5.7E-06～8.6E-05

3.2E-03
3.2E-03

時間・体積当たりの空間体積と持続時間
着火源の存在確率
急速冷媒漏洩
HFC32 室内機からの2.4E-02
min･m3
min/m3HFC32 5.7E-06～8.6E-05
発生頻度／ｙHC290冷媒漏洩発生確率
7.2E+03
HC290 5.7E-06～8.6E-05

冷媒漏洩
発生確率

バルブ誤動作
による漏洩
2.7

時間・体積
あたりの存在確
率
2.11

R290
R32

1.8E-10
1.8E-10～～

時間・体積当たりの着火源の存在確率
min/m3

2.7E-09
2.7E-09

可燃空間の
時間・体積
2.5

R290
R32

据付者が
指示を無視
2.17

喫煙しながら据付ける確率2.16

4.0E-06
4.0E-06
可燃空間の
時間・体積
2.2

可燃空間の
時間・体積
2.10

8.8E-08
1.0E-08

着火源が存在する

HC290 1.4E+01
1.2E+02
1.4E+00～～

HFC32 4.0E-07～5.0E-04
HFC32 0.4
HC290 4.0E-07～5.0E-04
HC290 0.4
HFC32 5.0E-04
HFC32 5.7E-06～8.6E-05
R290
R32

R290
R32

据付者の喫煙率2.15

時間・体積当たりの着火源の存在確率
HFC32 5.0E-04
HFC32 5.7E-06～8.6E-05
室内機からのmin/m3
6.0E-01
R290 2.0E-01
HC290 1.4E+01
R32HC290
6.0E-015.7E-06～8.6E-05
R290 2.0E-01
冷媒漏洩発生確率R290

R290
R32

時間・体積
あたりの存在確
率
2.11

工事不良
（接続ミス・忘れ）
による漏洩
2.12

R290
R32

R290
R32

1.4E-02
1.4E-02

4.0E-04
4.0E-04

HFC32 5.7E-06～8.6E-05
HC290 5.7E-06～8.6E-05
R290
R32

接続配管が
壁面内に存在
する確率
2.13

R290
R32

1.0E-01
1.0E-01

7.8E-02
9.0E-03

接続配管が着火源と同一
壁面に存在
2.14

R290
R32

R290
R32

工事不良
（接続ミス・忘れ）
による漏洩
2.8

4.4E-03
4.4E-03

R290
R32

5.7E-06
5.7E-06～～

8.6E-05
8.6E-05

冷媒漏洩
発生確率

R290
R32

可燃になる
空間体積と持続時間
min･m3R290
R32

4.4E-03
4.4E-03

バルブ誤動作
による漏洩
2.7

時間・体積
あたりの存在確率
2.11

R290
R32

4.3E-03
4.3E-03

冷媒充填時の接続不良による
漏洩
2.9

HFC32 2.4E-02
HC290 7.2E+03
R290
R32

4.4E-03
4.4E-03

1.7E-02
1.7E-02

サービスマン側へ冷媒が漏洩する
確率

時間・体積当たりの着火源の存在確率
min/m3
R290
R32

工事不良
（接続ミス・忘れ）
による漏洩
2.8

R290
R32

7.9E-03
7.9E-03

1.0E-01
1.0E-01～～

5.0E-01
5.0E-01

冷媒充填時の接続不良による
漏洩
2.9

HFC32 5.7E-06～8.6E-05
HC290 5.7E-06～8.6E-05
R290
R32

4.4E-03
4.4E-03

FTA of Install to Disposal

1.0E-01
1.0E-01© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1112． Results of risk assessment

Wall mount type air conditioner
Risk: Ignition Probability
R32

R1234yf(ref. R290)

Logistic

4.1×10-17

4.5×10-17

1.9×10-8~1.2×10-6

Installation

2.7×10-10

3.1×10-10

1.5×10-6~1.7×10-5

Use (Indoor)

3.9×10-15

4.3×10-15

5.9×10-9~1.1×10-4(Outdoor)

1.5×10-10

2.1×10-10

9.7×10-13~1.9×10-8

Service

3.2×10-10

3.6×10-10

9.3×10-6~1.7×10-5

Disposal

3.6×10-11

5.3×10-11

1.8×10-5~1.3×10-4

・Probability of indoor use is lower than tolerance level 10-10.
・Tolerance level 10-9 in service, installation and others is satisfied in all stages.
・The ignition probability of R32 and R1234yf is nearly same.
（Attention : R1234yf is extended flammable range in high humidity condition.
© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1213． Multi-split type air conditioner

Difference of ordinary and multi-split type air conditioner

Flammable volume

Flammable volume

・Issue : 4kg refrigerant amount and floor standing unite not satisfy to tolerance level© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1314． Multi-split type air conditioner

New simulation condition for floor mounted unite of multi-split
type air conditioner© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1415． Multi-split type air conditioner

Test results of refrigerant leakage inside room(approx. 7.5m2 room ）・Using the indoor unit fan to diffuse the refrigerant・In the case of 4 kg refrigerant leakage, LFL was not reached.
© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1516． Multi-split type air conditioner

・ Ratio of occurrence patterns and their ignition probabilities
in indoor use[Method 2]
Pattern

Diffusion
possible

Breaker
ON

Same as above

BreakerONPoweroutageBreakerOFF3
45Operating(indoor fan
ON)
Stop →
indoor fan
ON

In order toavoid breaker
OFF, add
caution label to
unit

2

Not
generalOperation /Stop

Diffusion
with I.U. fan

1
GeneralPower

Breaker OFF
countermeasureDiffusion notpossible

Parts
fault

Occurrence ratio

Ignition risk
probability

No48.80%

7.7-12

No50.91%

8.1-12

Yes

0.04%

5.6-11

No

0.002%

2.4-12No

0.25%

3.9-10Sum. ignition risk probability:

4.7-10Stop・ The ignition risk is 4.7×10-10 whenpatterns 1 to 5 are combined© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1617． Multi-split type air conditioner
Amount of multi-split AC in JapanType
Logistics(for each warehouse)
Installation
Use (indoor)
Use (outdoor)
Service
Disposal

Use Criteria10-9Service etc.10-8

Risk: Ignition Probability
Representative model

R32

Middle-size warehouse

1.1×10-09

3.24 m2 veranda
7 m2 room
3.24 m2 veranda
3.24 m2 veranda
3.24 m2 veranda

9.0×10-09
4.7×10-10
1.1×10-09
4.3×10-09
4.1×10-10

・In using the value of 10-9 estimate safety
・Probabilities of installation and servicing is acceptable© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

1718． Conclusion
Single wall mount AC Risk Assessment●Calculate the ignition probability values by FTA through life cycle
and reexamination by study results of universities and AIST
●Result of single wall mounted air conditioner with R32 and R1234yf
Using :1×10-10 Service & Install ：1×10-9 ⇒ Those values are acceptable★Using of R1234yf , be attention to the humidity and the HEX design
Multi-split type AC Risk Assessment●Result of Multi-split type air conditioner
With countermeasure of fun diffusion make value of Using :1×10-9
and service and install ：1×10-8⇒ Those vales are acceptable

Universities : Tokyo university, Tokyo university of science Suwa
AIST : The National Institute of Advanced Industrial Science and Technology© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

18

Thank you very much

mildly flammable

R32© 2015 JRAIA The Japan Refrigeration and Air Conditioning Industry Association. All Rights Reserved.

yf19