Refrigerant Safety / Selecting Piping - LG ARND DCR4 Series Installation Manual

GENERAL REFRIGERANT PIPING SYSTEM
Refrigerant Safety Standards
ASHRAE Standards 15-2010 and 34-2010 address refrigerant safety and the maximum allowable concentration of refrigerant in an occupied
space. Refrigerant will dissipate into the atmosphere, but a certain volume of air is required to safely dissipate the refrigerant. For R410A
refrigerant, the maximum allowable concentration of refrigerant is 26 lbs./1,000 cubic feet (Addendum L modified the RCL to 26) of occupied
spaces. Buildings with 24-hour occupancy allow half of that concentration.
If a VRF system develops a refrigerant leak, the entire refrigerant charge of the system will dump into the area where the leak occurs. To
meet ASHRAE Standards 15 and 34, the smallest room volume on the system must be calculated and compared to the maximum allowable
concentration. If the concentration level is higher than allowed, the following are some design suggestions to eliminate the problem:
• Split dual-frame and triple-frame systems into single-frame systems that have lower refrigerant charges.
• Add transfer grilles in the ceiling or walls of the smaller rooms to increase the volume of the room.
• Remove the smallest space from the system and serve it with a smaller mini-split system.
Selecting Field-Supplied Copper Piping For DOAS Units
LG prefers the use of hard drawn copper in pipe segments connecting a Dedicated Outdoor Air System (DOAS) product and a heat recovery
outdoor unit.
Table 5: ACR Rated Copper Tubing Material.
Type
Class
Straight Lengths
Coils
Table 6: ACR Rated Piping Wall Thicknesses.
OD (in)
Material Rigid or Soft ACR Rated for R410A
Min. Bend Radius (in) 0.563
Min. Wall Thickness (in)
Table 7: ACR Copper Tubing Dimensions and Physical Characteristics
Nominal Pipe
Actual Outside
Outside
Diameter (in)
Diameter (in)
1/4 0.250
3/8 0.375
1/2 0.500
5/8 0.625
3/4 0.750
7/8 0.875
1-1/8 1.125
All dimensions provided are in accordance with ASTM B280 – Standard.
1
Design pressure = 551 psig.
2
3 The Copper Tube Handbook, 2010, Copper Development Association Inc., 260 Madison Avenue, New York, NY 10016.
• Commercially available piping often contains dust and other materials. Always blow it clean with a dry nitrogen.
• Prevent dust, water or other contaminants from entering the piping during installation.
Seamless Phosphorous Deoxidized
1/4 3/8 1/2
0.9375 1.5
0.03 0.03 0.03
Tempered (Hard Drawn)
Nominal Wall
Weight (lb/ft)
Thickness (in)
--
0.030 0.126
0.035 0.198
0.040 0.285
0.042 0.362
0.045 0.455
0.050 0.655
Due to our policy of continuous product innovation, some specifications may change without notification.
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Refrigerant Safety / Selecting Piping

UNS C12200 DHP
H58 Temper
O60 Temper
5/8 3/4
Rigid or Soft ACR Rated for R410A
2.25 3.0
0.03 0.03
1-3
Cubic ft per Nominal Wall
Linear ft Thickness (in)
-- --
0.00054
0.00101
0.00162
0.00242
0.00336
0.00573
7/8 1-1/8 1-3/8
3.0 3.5 4.0
0.03 0.03 0.04
Annealed (Soft)
Weight (lb/ft)
0.030 0.081
0.032 0.134
0.032 0.182
0.035 0.251
0.042 0.362
0.045 0.455
0.050 0.655
1-5/8
4.5
0.050
Cubic ft per
Linear ft
0.00020
0.00053
0.00103
0.00168
0.00242
0.00336
0.00573
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