Fig 542L Pressure Relief Valve

Features

Pipe Connections

Screwed female inlet and outlet connections. inlet and outlet connections are of equal size. Threaded connections are Rp BSP parallel to BS EN 10226-1 NPT connections are available upon request.

Testing

All valves are shell and seat tested (to confirm set pressure) before leaving the factory and all valves are supplied pre-set with a tamper proof seal. Pressure Test Certificate and Letters of Conformity available on request.

Product Extras

Available with Viton seat design
Pressure setting locked and sealed
Drain plug fitted on sizes DN40 and above allows fitting of a pressure gauge

Fig 542L Pressure Relief Valve Dimensional Drawing

Dimensions & Weights

SIZE DN	Rp BSP Inlet & Outlet	A (mm)	B (mm)	C (mm)	Weight (Kg)
15	1/2″	30	23	113	0.50
20	3/4″	34	23	118	0.70
25	1″	39	27	132	0.93
32	1 1/4″	46	33	158	1.50
40	1 1/2″	54	38	200	2.41
50	2″	64	46	239	4.32
65	2 1/2″	76	55	285	8.24
80	3″	90	65	345	12.60

Materials

Ref No	Name of Part	Material
1	Leak Proof Dome	Bronze, BS EN 1982 CC491K
2	Locknut	Brass, BS EN 12164 CW609N
3	Dome ‘O’ Ring	Viton
4	Spring	Chrome Vandium Alloy Steel, BS 2803 735 A50 HS (Stainless Steel, BS 2056 302S26 Opt)
5	Label	Yellow kapton
6	Spring Cover	Bronze, BS EN 1982 CC491K
7	Piston	Brass, BS EN 12164 CW609N
8	Cover Seal	Viton
9	Seat Seal Holder	Bronze, BS EN 1982 CC491K / Brass BS EN 12164 CW602N (DZR)
10	Seat Seal	PTFE (Viton Opt)
11	Starlock Washer	Stainless Steel
12	Body	Bronze, BS EN 1982 CC491K
13	Adjusting Screw	Brass, BS EN 12164 CW609N
14	Spring Plate	Brass, BS EN 12164 CW609N
15	Spindle	Brass, BS EN 12164 CW721R
16	Seat Seal Retaining Plate	Bronze, BS EN 1982 CC491K / Brass BS EN 12164 CW602N (DZR)
17	O-Ring	Viton

Downloads

Bim

BIM Library

Discharge

Discharge Capabilities

The discharge capacity of a safety valve must be equal to or greater than the output of the boiler or system it is protecting. To ensure that the correct method of sizing is used, reference should be made to the relevant BS specification for the design of the boiler or system. Fig 542L capacities are tabulated below to assist selection.

Fig 542L – Air Capacity – 10% Overpressure (BS EN 4126-1) Click to View +

std. litres/sec

Set Pressure Bar	15	20	25	32	40	50	65	80
1.00	10	18	28	46	72	113	191	289
1.25	12	20	32	52	82	128	216	327
1.50	13	23	36	58	91	143	241	365
1.75	14	25	39	64	101	157	266	403
2.00	16	28	43	71	110	172	291	441
2.25	17	30	47	77	120	187	316	479
2.50	18	32	50	83	129	202	341	517
2.75	20	35	54	89	139	217	366	554
3.00	21	37	58	95	148	231	391	592
3.25	22	39	62	101	158	246	416	630
3.50	24	42	65	107	167	261	441	668
3.75	25	44	69	113	177	276	466	706
4.00	26	46	73	119	186	291	491	744
4.25	28	49	76	125	196	305	516	782
4.50	29	51	80	131	205	320	541	820
4.75	30	54	84	137	214	335	566	857
5.00	32	56	87	143	224	350	591	895
5.25	33	58	91	149	233	364	616	933
5.50	34	61	95	155	243	379	641	971
5.75	36	63	99	161	252	394	666	1009
6.00	37	65	102	167	262	409	691	1047
6.25	38	68	106	174	271	424	716	1085
6.50	40	70	110	180	281	438	741	1123
6.75	41	73	113	186	290	453	766	1160
7.00	42	75	117	192	300	468	791	1198
7.25	44	77	121	198	309	483	816	1236
7.50	45	80	124	204	319	498	841	1274
7.75	46	82	128	210	328	512	866	1312
8.00	48	84	132	216	338	527	891	1350
8.25	49	87	136	222	347	542	916	1388
8.50	50	89	139	228	357	557	941	1426
8.75	52	91	143	234	366	572	966	1464
9.00	53	94	147	240	375	586	991	1501
9.25	54	96	150	246	385	601	1016	1539
9.50	56	99	154	252	394	616	1041	1577
9.75	57	101	158	258	404	631	1066	1615
10.00	58	103	161	264	413	646	1091	1653
10.25	60	106	165	270	423	660	1116	1691
10.50	61	108	169	277	432	675	1141	1729

Fig 542L – Water Capacity – 10% Over Pressure (BS EN 4126-1) Click to View +

kg/min

Set Pressure Bar	15	20	25	32	40	50	65	80
1.00	22	40	62	102	159	248	419	635
1.25	25	44	69	114	178	277	469	710
1.50	27	49	76	124	195	304	514	778
1.75	30	52	82	134	210	328	555	840
2.00	32	56	88	144	225	351	593	898
2.25	34	60	93	152	238	372	629	953
2.50	35	63	98	161	251	392	663	1004
2.75	37	66	103	168	263	411	695	1053
3.00	39	69	107	176	275	430	726	1100
3.25	40	72	112	183	286	447	756	1145
3.50	42	74	116	190	297	464	784	1188
3.75	43	77	120	197	308	480	812	1230
4.00	45	79	124	203	318	496	839	1270
4.25	46	82	128	209	327	511	864	1309
4.50	47	84	132	216	337	526	889	1347
4.75	49	86	135	221	346	541	914	1384
5.00	50	89	139	227	355	555	938	1420
5.25	51	91	142	233	364	568	961	1455
5.50	52	93	146	238	373	582	983	1490
5.75	54	95	149	244	381	595	1005	1523
6.00	55	97	152	249	389	608	1027	1556
6.25	56	99	155	254	397	620	1048	1588
6.50	57	101	158	259	405	632	1069	1619
6.75	58	103	161	264	413	645	1089	1650
7.00	59	105	164	269	420	656	1109	1680
7.25	60	107	167	274	428	668	1129	1710
7.50	61	109	170	278	435	679	1148	1739
7.75	62	110	173	283	442	691	1167	1768
8.00	63	112	176	287	449	702	1186	1796
8.25	64	114	178	292	456	713	1204	1824
8.50	65	116	181	296	463	723	1222	1852
8.75	66	117	184	301	470	734	1240	1879
9.00	67	119	186	305	477	744	1258	1905
9.25	68	121	189	309	483	754	1275	1932
9.50	69	122	191	313	490	765	1292	1958
9.75	70	124	194	317	496	775	1309	1983
10.00	71	125	196	321	502	784	1326	2009
10.25	72	127	199	325	509	794	1342	2033
10.50	72	129	201	329	515	804	1359	2058

To convert to galls/min multiply by 0.22.

Product Search

Pressure Relief Valve

Features

Downloads

Bim

BIM Library

Discharge

Ecommerce is currently unavailable