Risk Assessment for Commercial Package Air Conditioners
Working Group for Risk Assessment of Lower Flammability refrigerant

IntroductionConclusion[Subject system] Commercial package air conditioners using A2L[Refrigerants (A2L)] R32, R1234yf, R1234ze(E)[Conditions of risk assessment]• Standard case : No problem without additional safety measures• Higher risk case : Some conditions need the following safety measure
Risk cases• 1st step: Standard case
(IU)Ceiling cassette, (OU) Ground, No additional refrigerant charge• 2nd step: Higher risk case less than 14kW system(IU)All type excluding floor mounted,€(OU) each floor installation, semi-underground, narrow space,(Max amount) Additional refrigerant charge on site
• 3rd step: Higher risk case less than 30kW system(IU)All type including floor mounted,(OU) each floor installation, semi-underground, narrow space,(Max amount) Additional refrigerant charge on site

Floor- standindoor units
Outdoors
Semiundergroundinstallation
Outdoors
Narrow space
installation※(IU): Indoor units, (OU): Outdoor units< Dominant risk factors >Cause
FactorSafetymeasures
CauseFactorSafetymeasures
Cause
FactorSafetymeasures

Usage stage• Cooling capacity: 3.6 ~ 30.0 kW• Charge amount of refrigerant: 2 ~ 19Kg
• Type: indoor single or 2~4 units in one room
[simultaneous ON/OFF],outdoor single

Disposal stage

Leakage gas retention
Leakage gas retention
Human error
High concentration
Air circulation by fan
Gas burner (brazing)“Education for workers” and“Unit’s fan operating with a leak detector”(Min. air flow: 10m3/min and Min. velocity: 1.0m/s) “Carrying a portable leak detector”
Leakage gas retentionIgnition sources
Human error
Refrigerant recovery
Refrigerant recovery
Air circulation/Ventilation
Boiler
Gas burnerElectrical wiring“Unit’s fan operating with a leak detector”“Education for workers” and(Minimum air velocity: 4.0m/s)“Carrying a leak detector”
Leakage gas retention
Ignition sources
Human error
Refrigerant recovery
Refrigerant recovery
Air circulation/Opening
Boiler
Gas burnerElectrical wiring“Education for workers” and“Opening of 0.6 m or more for one side”“Carrying a portable leak detector”

Installation

SystemInstallation/Service stages

Risk case• Total number of unit :about 0.6 billion units in Japan• User : Office, Store, School, etc.
(light commercial)

Leak rate

Flammable volume-time integration[Indoor unit]• 1.03 × 10-3 for slow leakage• 1.50 × 10-5 for rapid leakage[Outdoor unit]• 6.13 × 10-2 for slow leakage• 1.34 × 10-3 for rapid leakage• 1.37 × 10-4 for burst leakage[Human error (by worker)]• 1.0 × 10-3

[Indoor]• (Cassette 14kW,57.2m2, R32:8kg) 1.53× 10-1 [m3min]• (Floor 5kW,14m2, R32:3kg, Fan:OFF) 3.23× 102 [m3min]• (Floor 5kW,14m2, R32:3kg, Fan:ON) None
[Outdoor]• (Ground14kW, 50m2, R32:8kg) 2.80× 10-1 [m3min]• (Semi -underground, 15m2, R32:8kg) 5.97× 103 [m3min]• (Narrow[open0.3m], 7.5m2, R32:8kg) 9.75× 100 [m3min]• (Narrow[open0.6m], 7.5m2, R32:8kg) 3.75× 100 [m3min]

Not Acceptable[Indoor]• Floor mounted type indoor unit
[Outdoor]• Semi-underground installation• Narrow space installation

Ignition source[Spark]• Match, Oil lighter• Metal spark (by forklift)- (Ref.) No ignition - Gas lighter- Power Outlet- Static electricity (by human )[Open flame]• Smoking equipment• Combustion equipment(Heater, Boiler, Cooker etc.)• Gas burner (for brazing)

Riskassessment
Leak rate[Standard case (Refrigerant: R32)]< RA Condition >Location

FeatureOpening fornaturalIndoor
Officeventilation
Open all four
Outdoor Side flow
Groundsides
Storage
Bulk
Warehouse 2300 units
Ceiling
cassette

42.3

2.7

50
1000

2－Capacity(kW)

7.1
14.0
14.0

Pipinglength(m)≦30≦30－Charge
amount(kg)Condition

TypeLocation

FeatureIndoors
(Ice)

169

Ceiling

OfficeGroundOutdoors

Sideflow

Each floor
Semi-UG
Narrow S

StorageFloorarea(m2)

Max charge
Ignition
Ceiling
Kitchensources
Karaoke-room tightness
Restaurant Leakage gas
Floor
retention
Factory

OfficeIndoors

Installation space

Installation

Usage

Repair/Service

Disposal［Tolerable level］[ ≦ 1.3×10-8 ][ ≦ 1.3×10-8 ][ ≦ 1.3×10-9 ][ ≦ 1.3×10-8 ][ ≦ 1.3×10-8 ]Safety measures

Without

withwithout

withwithout

withwithout

withwithout

with(Indoors) Office－－

6.59×10-10

None

3.37×10-12None

1.19×10-10None

3.12×10-12None

4(Outdoors ) Ground－－

6.73×10-10None

6.35×10-11

None

2.23×10-10

None

6.05×10-11

None

4

Warehouse--------

3

Bulk

Warehouse

Charge rate
Open allfour sides
Close threesides
Close foursides
Open oneside(small)
2300units

Height(m)

2.7

30.0

Pipinglength(m)120Chargeamount(kg)Installation

Usage

Repair/Service

Disposal[Tolerable level][ ≦ 1.3×10-8 ][ ≦ 1.3×10-8 ][ ≦ 1.3×10-9 ][ ≦ 1.3×10-8 ][ ≦ 1.3×10-8 ]Safety measures

withoutwith

withoutwithwithoutwithwithout

withwithout

withOffice－－

6.61ｘ10-10

None

7.61×10-13

None

4.82×10-12None

1.90×10-12

None

Kitchen－－

6.75ｘ10-10

None

7.97×10-11None

1.65×10-10None

7.33×10-12

None

karaoke－－

6.77ｘ10-10None

8.71×10-11

None

1.04×10-9None

2.04×10-11

None

Restaurant－－

1.70ｘ10-8 2.45ｘ10-10 9.39×10-9 1.00ｘ10-12 9.28×10-9 2.81ｘ10-9

2.99ｘ10-9

None

－－

2.30ｘ10-9None

1.05×10-9None

3.11×10-9None

7.04×10-10None

6.68ｘ10-10None

3.62×10-12None

4.10×10-11None2.79×10-12None1930.0120

199.714100

2.42.533.6
4.5
30.05050120

3319502.714.075

9factory

19Ice TS30.0120Ground－－8.02ｘ10-10None

2.61×10-10None

5.53×10-10None

7.60×10-10

None

Each floor－－

1.00ｘ10-9None

6.15×10-10None

1.48×10-9None

2.01×10-9None

Semi underground－－3.67ｘ10-7 5.64ｘ10-9 4.65×10-6 1.14ｘ10-9 1.18×10-7 2.93ｘ10-9－－5.34ｘ10-9None--

3.6430.0120

1915.3

3.54

30.0120197.5

2.530.0120

19

Narrow space

7Warehouse

1000－

30.0－

Not tolerable

Logistics

2.7

2.5Tolerable,

Life stage

8050

1.55×10-11 None

< Result: Probability of Ignition >Capacity(kW)

Not tolerable

Logistics[Higher risk case (Refrigerant: R32)]< RA Condition >Introductio
nTolerable,

Life stage

Indoors

Type

Installation space
Floor
Heightarea(m2)(m)

Outdoors

Condition< Result: Probability of Ignition >8.30×10-11 None

1.43×10-7 1.59×10-9

8.49×10-9 3.97ｘ10-10 1.91×10-8 4.95ｘ10-10 2.61×10-8 2.84×10-9----3.51×10-9None

Documentation
1. Guideline of design construction for ensuring safety from commercial air conditioners using lower flammability (A2L) refrigerants JRA GL-16：2016
2. Requirements for ensuring safety against refrigerant leakage from commercial air conditioners using lower flammability (A2L) refrigerants JRA 4070：2016