ISO 5211 Mounting & Dimensions Guide

Overview

ISO 5211 is the international standard defining the interface between quarter-turn actuators and valves.
It standardises:

The flange size designation (F03 – F30)

Bolt circle diameter (PCD) and hole size/thread

Drive type (square or double-D) and stem dimensions

This ensures interchangeability, faster assembly, and simplified selection for actuated ball, butterfly, and plug valves.

Why ISO 5211 Matters

Universal fitment — mix and match actuator and valve brands easily

Consistent torque transfer — precision square or double-D stem drives

No custom brackets — standard bolt circles and coupler interfaces

Reduced downtime — simplified replacement or upgrade process

ISO 5211 Mounting Dimensions 

ISO 5211	d1	d2	d3	d4	h1 max	h2 min	Bolts / Studs
F03	46	25	36	M5	3	8	4
F04	54	30	42	M5	3	8	4
F05	65	35	50	M6	3	9	4
F07	90	55	70	M8	3	12	4
F10	125	70	102	M10	3	15	4
F12	150	85	125	M12	3	18	4
F14	175	100	140	M16	4	24	4
F16	210	130	165	M20	5	30	4
F25	300	200	254	M16	5	24	8
F30	350	230	298	M20	5	30	8
F35	415	260	356	M30	5	45	8
F40	475	300	406	M36	8	54	8
F48	560	370	483	M36	8	54	12
F60	686	470	603	M36	8	54	20

Note: The ISO 5211 standard allows for both tapped or through holes. Always check the actuator drawing to confirm whether bolts are inserted from above (through-holes) or into tapped threads.

Need Assistance?

Q: How do I work out which ISO5211 mount I have?

A: Measure across the mounting holes and compare to the dimensions table, example below is F05/F07, inside bolt holes measure as F05, and the outer holes are F07

Concentrate on the F05, as this is where the bolts are located in this instance.

Drive Types

Drive Type	Description	Typical Use
Square	Most common (across-flats drive). Allows precise torque transfer.	Ball and butterfly valves
Double-D	Stem has two parallel flats; used for compact couplers.	Compact electric actuators
Keyed Round	Stem with keyway for high-torque couplings.	Heavy-duty valves

Selecting the Correct ISO Mount

Measure valve stem (square AF or flat-to-flat on double-D).

Measure bolt circle (PCD) and hole type (threaded / clearance).

Match to actuator data sheet for correct F-size.

Confirm torque – actuator output must exceed valve break torque × safety factor (usually 1.3–1.5).

Typical Pairings

ISO Size	Common Valve DN Range	Typical Actuator Type
F03 – F04	DN8 – DN25 (¼″ – 1″)	Compact electric or rack & pinion pneumatic
F05 – F07	DN25 – DN65 (1″ – 2½″)	Standard pneumatic / electric
F10 – F12	DN80 – DN150 (3″ – 6″)	Medium torque pneumatic
F14 – F16	DN200 – DN300 (8″ – 12″)	Heavy-duty actuators
F25 – F30	DN350 – DN600 (14″ – 24″)	High-torque electric / hydraulic

FAQs

Q: Does ISO 5211 specify torque or pressure?
A: No – it standardises only the mechanical interface. However torque values are limited by ISO sizing. See below table of torque values.

Q: Can I use F05 actuator on F07 valve?
A: Not directly. You’ll need an adapter bracket or ISO conversion plate. But check the actuator has the required torque for the valve plus 30-50% safety margin.

Q: Are stainless actuator mounts standardised?
A: Yes – as long as dimensions match ISO 5211, the material is optional (aluminium, steel, stainless, or reinforced polymer).

Q: Will I need a drive adaptor?

A: possibly if the valve stem is smaller than the actuator drive socket. See below ISO5211 drive adaptors

ISO5211 Torque Chart

ISO5211 type	Maximum torque (Nm)
F03	32
F04	63
F05	125
F07	250
F10	500
F12	1000
F14	2000
F16	4000
F25	8000
F30	16000
F35	32000
F40	63000
F48	125000
F60	250000
F80	500000
F100	1000000

View our range of ISO5211 Valves & Actuators

Need Assistance?

Our engineering team can confirm actuator-valve compatibility across all ISO 5211 flange sizes (F03–F30) for all Pneumatic and electric actuators

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