Full Opening Check Valve - Knowledge - GNEE Multinational Trade

A full opening check valve is the one valve in a piggable line that nobody can open for the pig. The disc moves because the flow moves it, and on the day a tool arrives the disc is wherever the hydraulics left it. That is the first thing to understand about the product, and it is not what the name promises: full opening is a bore category in API 6D, defined by a table of minimum diameters, and from Class 1500 upward that minimum is smaller than the 95 percent gauge plate most pipeline operators run. Two numbers decide whether the valve works in your line - the bore against your pipe schedule, and the clearance the tool needs - and neither of them appears on a competitor's datasheet.

General Features

Full-port piggable

In-line repairable

Optional drain valve

Support leg on NPS 4 and larger

Lifting eye bolts on NPS 4 and larger

Suitable for horizontal and vertical (flow-up) installation. Technical evaluation required for vertical installation.

Optional slow closing device

Seat Design Features

Soft sealed

Soft Seated
Double seals (soft+HF)
Replaceable seat ring/o-ring
Optional thread seat
Internal hinge pin to minimize external leakage and ensure reliability in service

Metal Sealed

Metal Seated
Wear-resistant sealing surface
Quick closure to prevent backflow
Internal hinge pin to minimize external leakage and ensure reliability in service.

Cover Features

Independent dual cover seals (non-pressure seal design)

Optional Features

Drain plug

Outside mounted weight or dashpot

Design Standards

Basic Design	API 6D
Face to Face/End to End	ASME B16.10
Flange End	ASME B16.5/ASME B16.47
Butt-welding End	ASME B16.25
Testing	API 6D
Pressure-temperature Rating	ASME B16.34

Drawing for Soft Seated Valve

Material of Construction

Part No.	Part Name	Carbon Steel	Low Temperature	Stainless Steel
1	Body	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
2	O-Ring	NBR/HNBR/VITON	NBR/HNBR/VITON	NBR/HNBR/VITON
3	O-Ring	NBR/HNBR/VITON	NBR/HNBR/VITON	NBR/HNBR/VITON
4	Seat	ASTM A182 F6a+HF*	ASTM A182 F316+HF*	ASTM A182 F316*HF
5	Disc	ASTM A216 WCC+410	ASTM A352 LCC+316	ASTM A351 CF8M
6	Washer	ASTM A276 410	ASTM A276 316	ASTM A276 316
7	Cotter Pin	ASTM A276 316	ASTM A276 316	ASTM A276 316
8	Nut	ASTM A194 2HM	ASTM A194 7M	ASTM A194 8M
9	Rocker Arm	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
10	Screw	ASTM A276 304	ASTM A276 304	ASTM A276 304
11	Key	ASTM A276 316	ASTM A276 316	ASTM A276 316
12	Hinge Pin	ASTM A276 316	ASTM A276 316	ASTM A276 316
13	O-Ring	NBR/HNBR/VITON	NBR/HNBR/VITON	NBR/HNBR/VITON
14	Gasket	SS316+Graphite	SS316+Graphite	SS316+Graphite
15	Cover	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
16	Nut	ASTM A194 2HM	ASTM A194 7M	ASTM A194 8M
17	Stud	ASTM A193 B7M	ASTM A193 L7M	ASTM A193 B8M
18	Lifting Eyebolt	Carbon Steel	Carbon Steel	Carbon Steel
19	Plug	SS316	SS316	SS316
20	Nut	ASTM A194 2HM	ASTM A194 7M	ASTM A194 8M
21	Stud	ASTM A193 B7M	ASTM A193 L7M	ASTM A193 B8M
22	Gland	ASTM A350 LF2	ASTM A350 LF2	ASTM A276 316
23	Gasket	SS316+Graphite	SS316+Graphite	SS316+Graphite
24	O-Ring	NBR/HNBR/VITON	NBR/HNBR/VITON	NBR/HNBR/VITON
25	Spacer	ASTM A276 316	ASTM A276 316	ASTM A276 316
26	Packing	Graphite	Graphite	Graphite
27	Washer	Nitronic 60	Nitronic 60	Nitronic 60
28	Packing	Graphite	Graphite	Graphite
29	Bushing	Nitronic 60	Nitronic 60	Nitronic 60

Drawing for Metal Seated Valve

Drawing For Metal Seated Valve

Material of Construction

Part No.	Part Name	Carbon Steel	Low Temperature	Stainless Steel
1	Body	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
2	Seat	ASTM A105+HF *	ASTM A350 LF2+HF *	ASTM A182 F316+HF
3	Disc	ASTM A216 WCC+410	ASTM A352 LCC+316	ASTM A351 CF8M
4	Rocker Arm	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
5	Washer	ASTM A276 410	ASTM A276 316	ASTM A276 316
6	Cotter Pin	ASTM A276 316	ASTM A276 316	ASTM A276 316
7	Nut	ASTM A194 2HM	ASTM A194 7M	ASTM A194 8M
8	Gasket	SS316+Graphite	SS316+Graphite	SS316+Graphite
9	Cover	ASTM A216 WCC	ASTM A352 LCC	ASTM A351 CF8M
10	Nut	ASTM A194 2HM	ASTM A194 7M	ASTM A194 8M
11	Stud	ASTM A193 B7M	ASTM A193 L7M	ASTM A193 B8M
12	Lifting Eye Bolt	Carbon Steel	Carbon Steel	Carbon Steel
13	Plug	SS316	SS316	SS316
14	Washer	ASTM A276 410	ASTM A276 316	ASTM A276 316
15	Hinge Pin	ASTM A276 316	ASTM A276 316	ASTM A276 316
16	Anti–rotation Pin	ASTM A105	ASTM A350 LF2	ASTM A276 316

Dimension & Weight

CLASS 150

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	49	1.94	203	8.00	216	8.50	150	5.90	80	3.20	21	46
3	75	74	2.94	241	9.50	254	10.00	175	6.90	100	3.90	30	66
4	100	100	3.94	292	11.50	305	12.00	200	7.90	120	4.70	52	115
6	150	150	5.94	356	14.00	368	14.50	250	9.80	145	5.70	80	176
8	200	201	7.94	495	19.50	508	20.00	360	14.20	180	7.10	132	291
10	250	252	9.94	622	24.50	635	25.00	415	16.30	210	8.30	210	463
12	300	303	11.94	699	27.50	711	28.00	470	18.50	250	9.80	320	706
14	350	334	13.19	787	31.00	800	31.50	545	21.50	275	10.80	400	882
16	400	385	15.19	864	34.00	876	34.50	575	22.60	305	12.00	630	1389
18	450	436	17.19	978	38.50	991	39.00	605	23.80	325	12.80	850	1874
20	500	487	19.19	978	38.50	991	39.00	625	24.60	360	14.20	930	2051
24	600	589	23.19	1295	51.00	1308	51.50	745	29.30	430	16.90	1230	2712
26	650	633	24.94	1295	51.00	–	–	830	32.70	460	18.10	–	–
28	700	684	26.94	1448	57.00	–	–	900	35.40	500	19.70	–	–
30	750	735	28.94	1524	60.00	–	–	930	36.60	525	20.70	–	–
32	800	779	30.69	1524	60.00	–	–	980	38.60	580	22.80	–	–
36	900	874	34.44	1956	77.00	–	–	1120	44.10	635	25.00	–	–
40	1000	976	38.44	–	–	–	–	–	–	–	–	–	–
42	1050	1020	40.19	–	–	–	–	–	–	–	–	–	–
48	1200	1166	45.94	–	–	–	–	–	–	–	–	–	–

CLASS 300

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	49	1.94	267	10.50	283	11.13	150	5.90	90	3.50	25	55
3	80	74	2.94	318	12.50	333	13.13	175	6.90	110	4.30	36	79
4	100	100	3.94	356	14.00	371	14.63	200	7.90	140	5.50	56	124
6	150	150	5.94	445	17.50	460	18.13	250	9.80	170	6.70	88	194
8	200	201	7.94	553	21.00	549	21.63	360	14.20	190	7.50	145	320
10	250	252	9.94	622	24.50	638	25.13	415	16.30	235	9.30	226	498
12	300	303	11.94	711	28.00	727	28.63	470	18.50	275	10.80	350	772
14	350	334	13.19	838	33.00	854	33.63	550	26.60	300	11.80	420	926
16	400	385	15.19	864	34.00	879	34.63	580	22.80	340	13.40	665	1466
18	450	436	17.19	978	38.50	994	39.13	620	24.40	365	14.40	900	1985
20	500	487	19.19	1016	40.00	1035	40.75	650	25.60	400	15.70	1050	2315
24	600	589	23.19	1346	53.00	1368	53.88	780	30.70	475	18.70	1560	3440
26	650	633	24.94	1346	53.00	1372	54.00	850	33.50	525	20.70	1880	4145
28	700	684	26.94	1499	59.00	1524	60.00	930	36.60	560	22.00	2050	4520
30	750	735	28.94	1594	62.75	1619	63.75	950	37.40	600	23.60	2350	5182
32	800	779	30.69	–	–	–	–	1080	42.50	650	25.60	2550	5623
36	900	874	34.44	2083	82.00	2112	83.13	1260	49.60	670	26.40	2860	6306
40	1000	976	38.44	–	–	–	–	–	–	–	–	–	–
42	1050	1020	40.19	–	–	–	–	–	–	–	–	–	–
48	1200	1166	45.94	–	–	–	–	–	–	–	–	–	–

CLASS 600

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	49	1.94	292	11.50	295	11.63	220	8.70	92	3.60	35	77
3	80	74	2.94	356	14.00	359	14.13	270	10.60	114	4.50	55	121
4	100	100	3.94	432	17.00	435	17.13	285	11.20	150	5.90	90	199
6	150	150	5.94	559	22.00	562	22.13	340	13.40	191	7.50	150	331
8	200	201	7.94	660	26.00	664	26.13	480	18.90	230	9.10	285	628
10	250	252	9.94	787	31.11	791	31.13	550	21.70	280	11.00	470	1036
12	300	303	11.94	838	33.00	841	33.13	620	24.40	300	11.80	600	1323
14	350	334	13.19	889	35.00	892	35.13	650	25.60	320	12.60	640	1411
16	400	385	15.19	991	39.00	994	39.13	725	28.50	356	14.00	900	1985
18	450	436	17.19	1092	43.00	1095	43.13	820	32.30	390	15.40	1170	2580
20	500	487	19.19	1194	47.00	1200	47.25	840	33.10	430	16.90	1320	2911
24	600	589	23.19	1394	55.00	1407	55.38	850	33.50	485	19.10	2360	5204
26	650	633	24.94	1448	57.00	1461	57.50	960	37.80	560	22.00	–	–
28	700	684	26.94	1600	63.00	1613	63.50	1025	40.40	600	23.60	–	–
30	750	735	28.94	1651	65.00	1664	65.50	1100	43.30	630	24.80	4335	9559
32	800	779	30.69	1778	70.00	1794	70.63	1145	45.10	650	25.60	–	–
36	900	874	34.44	2083	82.00	2099	82.63	1260	49.60	720	28.30	–	–

CLASS 900

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	49	1.94	368	14.50	371	14.63	240	9.40	120	4.70	65	143
3	80	74	2.94	381	15.00	384	15.13	270	10.60	130	5.10	82	181
4	100	100	3.94	457	18.00	460	18.13	330	13.00	160	6.30	130	187
6	150	150	5.94	610	24.00	613	24.13	430	16.90	210	8.30	250	551
8	200	201	7.94	737	29.00	740	29.13	500	19.70	260	10.20	475	1047
10	250	252	9.94	838	33.00	841	33.13	580	22.80	290	11.40	600	1323
12	300	303	11.94	965	38.00	968	38.13	620	24.40	320	12.60	850	1874
14	350	322	12.69	1029	40.50	1038	40.88	650	25.60	320	12.60	1560	3440
16	400	373	14.69	1130	44.50	1140	44.88	700	27.60	365	14.40	1805	3980
18	450	423	16.69	1219	48.00	1232	48.50	760	29.90	400	15.70	2100	4631
20	500	471	18.56	1321	52.00	1334	52.50	830	32.70	450	17.70	–	–
24	600	570	22.44	1549	61.00	1568	61.75	1060	41.70	560	22.00	–	–

CLASS 1500

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	49	1.94	368	14.50	371	14.63	240	9.40	120	4.70	65	143
3	80	74	2.94	470	18.50	473	18.63	320	12.60	145	5.70	120	265
4	100	100	3.94	546	21.50	549	21.63	400	15.70	180	7.10	210	463
6	150	144	5.69	705	27.75	711	28.00	460	18.10	215	8.50	320	706
8	200	192	7.56	832	32.75	841	33.13	600	23.60	270	10.60	810	1786
10	250	239	9.44	991	39.00	1000	39.38	635	25.00	310	12.20	930	2051
12	300	287	11.31	1130	44.50	1146	45.13	725	28.50	360	14.20	1250	2756
14	350	315	12.44	1257	49.50	1276	50.25	760	29.90	400	15.70	1430	3153
16	400	360	14.19	1384	54.50	1407	55.38	820	32.30	450	17.70	–	–
18	450	406	16.00	1537	60.50	1559	61.38	930	36.60	500	19.70	–	–
20	500	454	17.88	1664	65.50	1686	66.38	930	37.80	520	20.50	–	–
24	600	546	21.50	1943	76.50	1972	77.63	1130	44.50	610	24.00	–	–

CLASS 2500

Size		B		L-RF/BW		L-RTJ		H		H1		Approx Weight
NPS	DN	mm	in	mm	in	mm	in	mm	in	mm	in	kg	lb
2	50	42	1.69	451	17.75	454	17.88	285	11.20	135	5.30	85	187
3	80	62	2.44	578	22.75	584	23.00	345	13.60	170	6.70	185	408
4	100	87	3.44	673	26.50	683	26.88	430	16.90	200	7.90	365	805
6	150	131	5.19	914	36.00	927	36.50	590	23.20	265	10.40	595	1312
8	200	179	7.06	1022	40.25	1038	40.88	680	26.80	300	11.80	815	1797
10	250	223	8.81	1270	50.00	1292	50.88	740	29.10	365	14.40	1250	2756
12	300	265	10.44	1422	56.00	1445	56.88	960	37.80	410	16.10	1460	3263

Reference Pressure/Temperature Chart

CV Value

NPS	CLASS 150	CLASS 300	CLASS 600	CLASS 900	CLASS 1500	CLASS 2500
2	91	91	76	65	60	48
3	211	211	176	151	139	111
4	380	380	317	272	251	201
5	571	571	476	408	377	301
6	845	854	704	604	557	446
8	1507	1507	1256	1077	993	795
10	2360	2360	1967	1686	1555	1244
12	3403	3403	2836	2431	2242	1794

notes

Note: Due to quick development of products, the data in our catalogue may be updated. GNEE reserves the right to change the design, material or specifications without prior notice and free of obligation to furnish or install such changes on products previously sold.

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FAQ

What is a full opening check valve?

A check valve whose closure member leaves an unobstructed circular bore when it is fully open, sized at or above the minimum API 6D sets for its size and class. In practice it is the swing type. The purpose is to let a pipeline pig pass, which is why the same valve is also sold as a piggable check valve.

Is full opening the same as full bore and full port?

Full bore and full opening are the same requirement, and full port is ball valve language for the same idea. All three describe a bore, not a clearance. A valve can be full opening to API 6D and still be 6.4 mm smaller than a 95 percent gauge plate at NPS 24 Class 1500, because the standard's figure is a floor.

What bore should I specify for a piggable line?

A number in millimetres, measured at the seat with the disc fully open. The usual wording is not less than 95 percent of the pipe ID at the specified schedule. If the order says only full opening to API 6D, it has specified a category, and from Class 1500 upward that category's floor is below the plate the operator will run.

Can a check valve be pigged with an intelligent pig?

Yes, if the bore and the pocket allow it, and the answer arrives as a drawing rather than a datasheet. Utility pigs with flexible discs cross a faired pocket. An intelligent pig with rigid arms and a body two to three diameters long needs the pocket faired and the seat ring flush, so ask where the smallest opening is and what it measures before the tool is booked.

Can the line be pigged in reverse through a check valve?

No. Reverse pigging is impossible through a check valve: the tool arrives at the back of a closed disc and there is no operator to open it. If the integrity plan pigs from both ends, the valve needs a bypass spool or the line needs a different isolation arrangement. Settle this first, because it changes the piping rather than the valve.

How do I keep the disc open while the pig passes?

Two ways, and only two. The first is a pigging rate high enough to hold the disc at full travel, stated in the procedure and checked against the pump curve. The second is a lock-open device, which needs the external hinge pin version and holds the disc out of the bore mechanically. A heavier dashpot is not a substitute for either.

What full opening check valve dimensions must I fix before ordering?

Three. Face-to-face in millimetres, from the ASME B16.10 long pattern column or from your spool drawing. Bore at the seat, as a number. And the end connection with its facing, including whether a Class 2500 flange exists in ASME B16.5 at your size. Everything else can be defaulted; these three cannot.

Is API 6D or API 594 the right design standard?

API 6D, for this product. API 594 covers wafer, lug and dual flange check valves in single and dual plate form and bolted cover swing checks, and it has no full opening category and no pig passage requirement. A listing that names both was copied from a template, and the clause you care about is in API 6D.

What pressure class can be made piggable?

At the standard's minimum bore, Class 150 through Class 900 in every size from NPS 6 upward. At Class 1500 the floor sits below a 95 percent plate in every size, and at Class 2500 it is 15.4 mm below at NPS 6, so those classes need the bore written as a number and confirmed by the mill. Above Class 900 the valves exist but are not catalogue items.

Do I need a dashpot or a counterweight?

You need one of them when the disc's natural closing time lands inside the reverse-flow window and the resulting surge is unacceptable. Fitting a dashpot to a valve that already closes quickly adds reverse flow; fitting a counterweight to a valve that is already slow adds surge. Ask for the closing time with and without the device, in seconds, and compare it with twice the pipe length over the wave speed for your line.

What seat material should a pigged line use?

Metal, with hardfacing on both faces, usually 13Cr on the disc and CoCr-A on the seat ring. A soft seat is wiped by the pig and cannot be repaired in the line. The acceptance rate moves with the choice: ISO 5208 Rate D for a metal seat, Rate A for a soft one, so a specification that asks for zero leakage and pigging is asking for two different valves.

What is the minimum order and lead time?

One piece. Common carbon steel sizes ship in about a week, built to order takes 10 to 15 working days, and alloy bodies or butt weld ends take 30 to 45 days. A dashpot, a counterweight or an external hinge pin adds to the built-to-order figure rather than to the stock one.

What documents come with the valve?

EN 10204 3.1 as standard and 3.2 when an inspector witnesses, a dimensional report that includes the measured bore and the face-to-face as built, PMI on pressure-containing parts, and the API 6D test records per serial number. Third-party inspection is scheduled to the production date rather than to packing, so that the shell test and the seat test can actually be seen.

What is the warranty, and what happens if it fails?

Eighteen months from shipment. The two failures this product actually produces are seat damage from a pig and bushing wear on the hinge pin, and both are repairable in line at most sizes because the seat ring is renewable and the cover is bolted. Spares are the seat ring, the disc, the pin and the bushings; they are matched to the body, so quote the serial number.