Refrigerant · HFC blend

R-508B pressure-temperature chart and data

R-23 / R-116. Safety class A1, GWP 13,396. Ultra-low temperature (about -100 °F). Replaced R-13 and R-503.

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R-508B data sheet

Made of	R-23 46 / R-116 54 (mass %)
Type	HFC blend
Safety class	A1 — lower toxicity, does not burn
Ozone depletion (ODP)	0
Global warming (GWP, 100 yr)	13,396
Boils at 1 atm	-125.8 °F (-87.7 °C)
Critical temperature	52.5 °F (11.4 °C)
Temperature glide	none / very small
Low side at 5 °F evaporating	259 psig (1788 kPa)
High side at 86 °F condensing	above the critical point, no condensing
Old cylinder colour	Navy
Oil	POE
Used for	Ultra-low temperature (about -100 °F). Replaced R-13 and R-503.

Pressures are saturation values from reference equations of state. Real pressures change with load and airflow. GWP is the IPCC AR4 100-year value (blends calculated from their ingredients). Cylinder colours were an old AHRI code; since 2020 new cylinders are all one colour with the name on the label, so always read the label, never go by colour.

R-508B pressure / temperature chart

°F	°C	psig	kPa
-60	-51.1	67.8	468
-59	-50.6	69.6	480
-58	-50.0	71.5	493
-57	-49.4	73.3	505
-56	-48.9	75.2	518
-55	-48.3	77.1	532
-54	-47.8	79.1	545
-53	-47.2	81.0	559
-52	-46.7	83.0	572
-51	-46.1	85.1	587
-50	-45.6	87.1	601
-49	-45.0	89.2	615
-48	-44.4	91.4	630
-47	-43.9	93.5	645
-46	-43.3	95.7	660
-45	-42.8	98.0	675
-44	-42.2	100	691
-43	-41.7	103	707
-42	-41.1	105	723
-41	-40.6	107	739
-40	-40.0	110	756
-39	-39.4	112	773
-38	-38.9	115	790
-37	-38.3	117	807
-36	-37.8	120	824
-35	-37.2	122	842
-34	-36.7	125	860
-33	-36.1	127	879
-32	-35.6	130	897
-31	-35.0	133	916
-30	-34.4	136	935
-29	-33.9	138	954
-28	-33.3	141	974
-27	-32.8	144	994
-26	-32.2	147	1014
-25	-31.7	150	1034
-24	-31.1	153	1055
-23	-30.6	156	1076
-22	-30.0	159	1097
-21	-29.4	162	1119
-20	-28.9	165	1141
-19	-28.3	169	1163
-18	-27.8	172	1185
-17	-27.2	175	1208
-16	-26.7	179	1231
-15	-26.1	182	1254
-14	-25.6	185	1278
-13	-25.0	189	1302
-12	-24.4	192	1326
-11	-23.9	196	1351
-10	-23.3	199	1375
-9	-22.8	203	1401
-8	-22.2	207	1426
-7	-21.7	211	1452
-6	-21.1	214	1478
-5	-20.6	218	1505
-4	-20.0	222	1531
-3	-19.4	226	1558
-2	-18.9	230	1586
-1	-18.3	234	1614
0	-17.8	238	1642
1	-17.2	242	1670
2	-16.7	246	1699
3	-16.1	251	1728
4	-15.6	255	1758
5	-15.0	259	1788
6	-14.4	264	1818
7	-13.9	268	1849
8	-13.3	273	1880
9	-12.8	277	1911
10	-12.2	282	1943
11	-11.7	287	1975
12	-11.1	291	2008
13	-10.6	296	2041
14	-10.0	301	2074
15	-9.4	306	2108
16	-8.9	311	2142
17	-8.3	316	2176
18	-7.8	321	2211
19	-7.2	326	2247
20	-6.7	331	2283
21	-6.1	336	2319
22	-5.6	342	2355
23	-5.0	347	2392
24	-4.4	352	2430
25	-3.9	358	2468
26	-3.3	364	2506
27	-2.8	369	2545
28	-2.2	375	2584
29	-1.7	381	2624
30	-1.1	386	2664
31	-0.6	392	2705
32	0.0	398	2746
33	0.6	404	2788
34	1.1	410	2830
35	1.7	417	2872
36	2.2	423	2915
37	2.8	429	2958
38	3.3	435	3002
39	3.9	442	3046
40	4.4	448	3091
41	5.0	455	3136
42	5.6	461	3182
43	6.1	468	3228
44	6.7	475	3274
45	7.2	482	3321
46	7.8	489	3368
47	8.3	495	3416
48	8.9	502	3465
49	9.4	510	3513

Critical temperature is 52.5 °F, so the chart stops just below it. Above that the gas cannot condense.

V = vacuum in inches of mercury. Saturation pressure in psig at sea level, calculated from reference equations of state. The chart gives the boiling temperature at that pressure, not the pipe temperature. Air in the system adds pressure and throws it off.

R-508B pressure in psig, psia, kPa and bar

°F	°C	psig	psia	kPa gauge	kPa absolute	bar absolute
-60	-51.1	67.8	82.5	468	569	5.69
-55	-48.3	77.1	91.8	532	633	6.33
-50	-45.6	87.1	101.8	601	702	7.02
-45	-42.8	98.0	112.7	675	777	7.77
-40	-40.0	110	124.3	756	857	8.57
-35	-37.2	122	136.9	842	944	9.44
-30	-34.4	136	150.3	935	1036	10.36
-25	-31.7	150	164.7	1034	1136	11.36
-20	-28.9	165	180.1	1141	1242	12.42
-15	-26.1	182	196.6	1254	1356	13.56
-10	-23.3	199	214.2	1375	1477	14.77
-5	-20.6	218	232.9	1505	1606	16.06
0	-17.8	238	252.8	1642	1743	17.43
5	-15.0	259	274.0	1788	1889	18.89
10	-12.2	282	296.5	1943	2044	20.44
15	-9.4	306	320.4	2108	2209	22.09
20	-6.7	331	345.8	2283	2384	23.84
25	-3.9	358	372.6	2468	2569	25.69
30	-1.1	386	401.1	2664	2766	27.66
35	1.7	417	431.3	2872	2973	29.73
40	4.4	448	463.0	3091	3192	31.92
45	7.2	482	496.4	3321	3422	34.22

V = vacuum in inches of mercury. Absolute pressure = gauge + 14.7 psi at sea level; use absolute pressure for gas-law work. For blends the dew column is the vapour (suction) side and the bubble column the liquid side.

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Calculation aids and reference figures for licensed technicians. Always follow the manufacturer’s data plate and manual for the exact model, and local codes. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Pressures are typical saturation values and change with load and airflow.