各国口径换算

公称英寸	英寸	公称通径dn	国标a	国标b	美标	日标
1/8“		6			10.3
1/4“		8			13.7
3/8“		10			17.1
1/2“	0.840	15	21.3	18	21.3
3/4“	1.050	20	26.9	25	26.7	27.2
1“	1.315	25	33.7	32	33.4	34
11/4”	1.660	32	42.4	38	42.2	42.7
11/2”	1.900	40	48.3	45	48.3	48.6
2“	2.375	50	60.3	57	60.3	60.5
21/2”	2.875	65	76.1	76	73.0	76.3
3“	3.500	80	88.9	89	88.9	89.1
31/2“		90			101.6	101.6
4“	4.500	100	114.3	108	114.3	114.3
5”	5.563	125	139.0	133	141.3	139.80
6”	6.625	150	168.3	159	168.3	165.20
8”	8.625	200	219.1	219	219.1	216.30
10”	10.750	250	273.0	273	273.1	267.40
12“	12.750	300	323.9	325	323.9	318.50
14”	14.000	350	355.6	377	355.6	355.60
16”	16.000	400	406.4	426	406.4	406.40
18“	18.000	450	457.0	478	457.2	457.20
20”	20.000	500	508.0	529	508.0	508.00
22”	22.000	550	559.0		558.8	558.00
24”	24.000	600	610.0	630	609.6	609.60
26”	26.000	650	660.0		660.4	660.40
28”	28.000	700	711.0	720	711.2	711.20
30”	30.000	750	762.0		762.0	762.00
32“	32.000	800	813.0	820	812.8	812.80
34“	34.000	850	864.0		863.6	863.60
36”	36.000	900	914.0	920	914.4	914.40
38“	38.000	950	965.0		965.2	965.20
40”	40.000	1000	1016.0	1020	1016.0	1016.00
42“	42.000	1050	1067.0		1066.8	1066.80
44“	44.000	1100	1118.0	1120	1117.6	1117.60
46“	46.000	1150	1168.0		1168.4	1168.40
48“	48.000	1200	1219.0	1220	1219.2	1219.20