Fig 542F Safety Relief Valve

Features

Pipe Connections

Flanged inlet connections. Threaded female outlet connections, Rp (BSP) parallel to BS EN 10226-1 Most flange standards can be accommodated.

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
Padlock available
Pressure setting locked and sealed
Drain plug fitted on sizes DN40 and above allows fitting of a pressure gauge

NABIC Fig 542F Safety Relief Valve Dimensional Drawing

Dimensions & Weights

SIZE DN	Inlet	Rp BSP Outlet	A (mm)	B (mm)	C (mm)	Weight (Kg)
32	Flanged	1 1/4″	46	60	180	3.00
40	Flanged	1 1/2″	54	64	225	4.40
50	Flanged	2″	64	73	263	7.15
65	Flanged	2 1/2″	76	83	303	10.00
80	Flanged	3″	90	96	366	16.41

Materials

Ref No	Name of Part	Material
1	Thrust Washer	Brass, BS EN 12164 CW609N
2	Grubscrew	Steel
3	Test Lever	Brass, BS EN 1982 CC754S
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	Diaphragm	Silicon Rubber
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	Lever Pin	Steel
14	Lead Seal (Not shown)	Lead
15	Adjusting Screw	Brass, BS EN 12164 CW609N
16	Spring Plate	Brass, BS EN 12164 CW609N
17	Spindle	Brass, BS EN 12164 CW721R
18	Seat Seal Retaining Plate	Bronze, BS EN 1982 CC491K / Brass BS EN 12164 CW602N (DZR)
19	O-Ring	Viton

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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 542F capacities are tabulated below to assist selection.

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

std. litres/sec (Kdr=0.19)

Set Pressure Bar	32	40	50	65	80
1.00	62	97	151	256	387
1.25	70	109	171	289	438
1.50	78	122	191	322	488
1.75	86	135	211	356	539
2.00	94	148	230	389	590
2.25	102	160	250	423	640
2.50	111	173	270	456	691
2.75	119	186	290	490	742
3.00	127	198	310	523	793
3.25	135	211	329	557	843
3.50	143	224	349	590	894
3.75	151	236	369	624	945
4.00	159	249	389	657	995
4.25	167	262	409	690	1046
4.50	175	274	428	724	1097
4.75	184	287	448	757	1147
5.00	192	300	468	791	1198
5.25	200	312	488	824	1249
5.50	208	325	507	858	1299
5.75	216	338	527	891	1350
6.00	224	350	547	925	1401
6.25	232	363	567	958	1451
6.50	240	376	587	992	1502
6.75	248	388	606	1025	1553
7.00	256	401	626	1059	1603
7.25	265	414	646	1092	1654
7.50	273	426	666	1125	1705
7.75	281	439	686	1159	1755
8.00	289	452	705	1192	1806
8.25	297	464	725	1226	1857
8.50	305	477	745	1259	1908
8.75	313	490	765	1293	1958
9.00	321	502	785	1326	2009
9.25	329	515	804	1360	2060
9.50	338	528	824	1393	2110
9.75	346	540	844	1427	2161
10.00	354	553	864	1460	2212
10.25	362	566	884	1494	2262
10.50	370	578	903	1527	2313

To convert to ft3/min multiply by 2.1.

Fig 542F – Steam Capacity – 10% Overpressure (BS 6759) Click to View +

Kg/hr (Kdr=0.19)

Set Pressure Bar	32	40	50	65	80
1.00	168	263	411	695	1053
1.25	190	298	465	786	1191
1.50	213	332	519	877	1329
1.75	235	367	573	968	1466
2.00	257	401	627	1059	1604
2.25	279	436	680	1150	1742
2.50	301	470	734	1241	1880
2.75	323	505	788	1332	2018
3.00	345	539	842	1423	2156
3.25	367	574	896	1514	2294
3.50	389	608	950	1605	2432
3.75	411	643	1004	1696	2569
4.00	433	677	1057	1787	2707
4.25	455	712	1111	1878	2845
4.50	477	746	1165	1969	2983
4.75	499	781	1219	2060	3121
5.00	521	815	1273	2151	3259
5.25	543	849	1327	2242	3397
5.50	565	884	1380	2333	3534
5.75	587	918	1434	2424	3672
6.00	610	953	1488	2515	3810
6.25	632	987	1542	2606	3948
6.50	654	1022	1596	2697	4086
6.75	676	1056	1650	2788	4224
7.00	698	1091	1704	2879	4362
7.25	720	1125	1757	2970	4500
7.50	742	1160	1811	3061	4637
7.75	764	1194	1865	3152	4775
8.00	786	1229	1919	3244	4913
8.25	808	1263	1973	3335	5051
8.50	830	1298	2027	3426	5189
8.75	852	1332	2080	3517	5327
9.00	874	1367	2134	3608	5465
9.25	896	1401	2188	3699	5603
9.50	918	1436	2242	3790	5740
9.75	940	1470	2296	3881	5878
10.00	962	1505	2350	3972	6016
10.25	984	1539	2404	4063	6154
10.50	1006	1574	2457	4154	6292

To convert to lb/hr multiply by 2.2.
The minimum bore size permitted by BS specifications for steam and hot water boilers is 20mm.

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

Kw (Kdr=0.19)

Set Pressure Bar	32	40	50	65	80
1.00	136	213	332	561	850
1.25	152	238	371	627	950
1.50	167	260	407	687	1041
1.75	180	281	439	742	1124
2.00	192	301	469	793	1202
2.25	204	319	498	842	1275
2.50	215	336	525	887	1344
2.75	225	352	550	930	1409
3.00	235	368	575	972	1472
3.25	245	383	598	1011	1532
3.50	254	398	621	1050	1590
3.75	263	412	643	1086	1646
4.00	272	425	664	1122	1700
4.25	280	438	684	1157	1752
4.50	288	451	704	1190	1803
4.75	296	463	723	1223	1852
5.00	304	475	742	1255	1900
5.25	312	487	761	1286	1947
5.50	319	498	778	1316	1993
5.75	326	510	796	1345	2038
6.00	333	521	813	1374	2082
6.25	340	531	830	1403	2125
6.50	347	542	846	1430	2167
6.75	353	552	862	1458	2208
7.00	360	562	878	1484	2249
7.25	366	572	894	1511	2288
7.50	372	582	909	1536	2327
7.75	378	592	924	1562	2366
8.00	385	601	939	1587	2404
8.25	390	611	953	1611	2441
8.50	396	620	968	1636	2478
8.75	402	629	982	1660	2514
9.00	408	638	996	1683	2550
9.25	413	646	1010	1706	2585
9.50	419	655	1023	1729	2619
9.75	425	664	1036	1752	2654
10.00	430	672	1050	1774	2687
10.25	435	680	1063	1796	2721
10.50	441	689	1076	1818	2754

To convert to Btu/hr multiply by 3400.

Fig 542F – Hot Water Capacity – 10% Overpressure (BS EN 4126-1) Click to View +

Kw (Kdr=0.19)

Set Pressure Bar	32	40	50	65	80
1.00	106	165	258	436	660
1.25	119	187	291	493	746
1.50	133	208	325	550	833
1.75	147	230	359	607	919
2.00	161	251	393	664	1005
2.25	175	273	426	721	1092
2.50	188	295	460	778	1178
2.75	202	316	494	835	1265
3.00	216	338	528	892	1351
3.25	230	359	561	949	1437
3.50	244	381	595	1006	1524
3.75	258	403	629	1063	1610
4.00	271	424	663	1120	1697
4.25	285	446	696	1177	1783
4.50	299	468	730	1234	1869
4.75	313	489	764	1291	1956
5.00	327	511	798	1348	2042
5.25	340	532	831	1405	2129
5.50	354	554	865	1462	2215
5.75	368	576	899	1519	2301
6.00	382	597	933	1576	2388
6.25	396	619	966	1633	2474
6.50	410	640	1000	1690	2561
6.75	423	662	1034	1747	2647
7.00	437	684	1068	1804	2733
7.25	451	705	1101	1861	2820
7.50	465	727	1135	1919	2906
7.75	479	748	1169	1976	2993
8.00	493	770	1203	2033	3079
8.25	506	792	1236	2090	3165
8.50	520	813	1270	2147	3252
8.75	534	835	1304	2204	3338
9.00	548	856	1338	2261	3425
9.25	562	878	1371	2318	3511
9.50	575	900	1405	2375	3597
9.75	589	921	1439	2432	3684
10.00	603	943	1472	2489	3770
10.25	617	965	1506	2546	3857
10.50	631	986	1540	2603	3943

In the above tables, discharge capacities have been calculated in accordance with BS EN 4126-1 & BS 6759, using a derated coefficient of discharge (Kdr) 0.19, approved by AOTC.

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