IDF Stainless Steel Fittings Dimensions

IDF (International Dairy Federation) is a hygienic pipe fitting standard used extensively across mainland Europe and internationally in dairy, food, and beverage processing. Like RJT and SMS, an IDF union consists of a male part and weld liner welded to the pipe ends, joined by a captive nut with a seal compressed between smooth, easily cleaned faces. IDF's thread form and sealing geometry are its own, distinct from both RJT and SMS, so parts between these standards don't mix even at the same nominal pipe size.

The charts below give dimensional information for IDF standard male, nut, weld liner, blank, and seal parts. Dimensions shown are in mm; if you wish to convert to inches, please use our universal converter.

Dimensional Charts relating to IDF Standard Male, Nut, Weld Liner, Blank and Seal Parts.

IDF fittings (International Dairy Federation) are used extensively in the UK and throughout Europe.

This is a hygienic fitting which has a smooth bore with a crevice free design.

This makes them suitable for CIP (clean in place technology).

Double flanged seals (T section) are supplied as standard and a less common single flanged (L section) can also be supplied.

Dimensions shown are in mm, if you wish to convert them, please use our universal converter.

IDF MALE PART DIMENSIONS - BS4825:4 1991

Nominal Size	Dimensions (mm)
	A	B	C	D	E
1 (25.4)	25.8	22.1	21.5	37.1 x 1/8	29.2
1 1/2 (38.1)	38.5	34.5	21.5	50.6 x 1/8	42.7
2 (50.8)	51.2	47.6	21.5	64.1 x 1/8	56.2
2 1/2 (63.5)	63.9	60.3	21.5	77.6 x 1/8	69.9
3 (76.2)	76.6	73.0	21.5	91.1 x 1/8	82.6
4 (101.6)	102.1	97.3	30.0	125.9 x 1/8	141.1

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IDF HEXAGON NUT DIMENSIONS - BS4825:4 1991

Nominal Size	Dimensions (mm)
	A	B	C	D
1 (25.4)	46.0	30.0	30.5	38.3 x 1/8
1 1/2 (38.1)	61.0	30.0	43.5	51.8 x 1/8
2 (50.8)	76.0	30.0	57.0	65.3 x 1/8
2 1/2 (63.5)	91.0	30.0	70.0	78.8 x 1/8
3 (76.2)	106.5	30.0	83.0	92.3 x 1/8
4 (101.6)	133.4	30.0	112.0	126.8 x 1/8

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IDF WELDING LINER DIMENSIONS - BS4825:4 1991

Nominal Size	Dimensions (mm)
	A	B	C	D	E
1 (25.4)	33.8	29.2	21.5	25.8	22.2
1 1/2 (38.1)	47.0	42.7	21.5	38.5	34.9
2 (50.8)	60.5	56.2	21.5	51.2	47.6
2 1/2 (63.5)	74.0	69.9	21.5	63.9	60.3
3 (76.2)	87.5	82.6	21.5	76.6	73.0
4 (101.6)	120.6	111.1	30.0	102.1	97.3

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IDF BLANK DIMENSIONS - BS4825:4 1991

Nominal Size	Dimensions (mm)
	A	B	C
1 (25.4)	29.2	33.8	10.6
1 1/2 (38.1)	42.7	47.0	10.6
2 (50.8)	56.2	60.5	10.6
2 1/2 (63.5)	69.9	74.0	10.6
3 (76.2)	82.6	87.5	10.6
4 (101.6)	111.0	120.6	10.6

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IDF SEAL DIMENSIONS - BS4825:4 1991

Nominal Size	Dimensions (mm)
	A	B	C
1 (25.4)	23.2	32.5	7.0
1 1/2 (38.1)	35.9	46.0	7.0
2 (50.8)	48.6	59.5	7.0
2 1/2 (63.5)	61.3	73.2	7.0
3 (76.2)	74.0	86.5	7.0
4 (101.6)	98.6	119.0	9.6

RELATED PAGES

• RJT Stainless Steel Fittings
• SMS Stainless Steel Fittings Dimensions
• DIN Stainless Steel Fittings Dimensions

FREQUENTLY ASKED QUESTIONS

Is IDF the same as ISS?

IDF fittings are sometimes referred to as ISS in some regions or supplier catalogues — check with your supplier if you see either term used, to confirm they mean the same dimensional standard before ordering.

How do I identify which hygienic fitting standard my existing pipework uses?

Measuring the thread form and comparing against the RJT, SMS, IDF, and DIN charts on this site is the most reliable way, since the fittings can look superficially similar at a glance. If in doubt, a sample part taken to a fitting supplier can usually be matched quickly.