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ACL® Clamp Nut Torque Guide
Introduction
The torque figures for ACL clamps are
based on the following assumptions:
- The torque values given are for the common sanitary union design.
- Torque figures are based on maintaining ASME-BPE SG-4.2 CAT II Intrusion.
- The figures are based on the maximum working pressure (MAWP).
- Ferrules and gaskets must conform to recognised industry standards and enable the correct assembly of the union with minimal gasket crevices.
- Polymeric gasket unions should be re-torqued after allowing some time for the gasket to creep.
- The torque figure can be reduced if the MAWP is reduced and ASME BPE categories of intrusion are adhered to. However, a minimum of 2Nm should be considered.
- Torque is applied in a slow and steady manner up to the required figure.
- A suitable sanitary lubricant must be used for threads on unions where PTFE is the seal material.
ACL® Clamps use a variety of thread sizes which have been selected for the clamping force requirement of each size and style of clamp.
Table 1. ACL® Clamp Bolt Sizes by Size and Type
| NOMINAL SIZE (INCHES) | SH | SSH | ASME VIII | S-TYPE |
|---|---|---|---|---|
| 0.5 | 5/16” UNC – 18 | M8 x 1.25 | – | 5/16” UNC – 18 |
| DN10 | 5/16” UNC – 18 | M8 x 1.25 | – | 5/16” UNC – 18 |
| 1.5 | 5/16” UNC – 18 | M10 x 1.25 | 1/2″ UNC – 13 | 5/16” UNC – 18 |
| 2 | 5/16” UNC – 18 | M10 x 1.25 | 1/2″ UNC – 13 | 5/16” UNC – 18 |
| 2.5 | 5/16” UNC – 18 | M10 x 1.25 | – | 5/16” UNC – 18 |
| 3 | 5/16” UNC – 18 | M10 x 1.25 | 1/2″ UNC – 13 | 5/16” UNC – 18 |
| 3.5 | 5/16” UNC – 18 | M10 x 1.25 | – | 5/16” UNC – 18 |
| 4 | 5/16” UNC – 18 | M10 x 1.25 | 1/2″ UNC – 13 | 5/16” UNC – 18 |
| 4.5 | 5/16” UNC – 18 | M10 x 1.25 | – | 5/16” UNC – 18 |
| 5 | 5/16” UNC – 18 | M12 x 1.75 | – | – |
| 5.5 | M10 x 1.5 | M12 x 1.75 | – | – |
| 6 | M10 x 1.5 | M12 x 1.75 | 1/2″ UNC – 13 | 5/16” UNC – 18 |
| 6.625 | M10 x 1.5 | M12 x 1.75 | – | – |
| 8 | M10 x 1.5 | M12 x 1.75 | 1/2″ UNC – 13 | – |
| 8.625 | M10 x 1.5 | M12 x 1.75 | 1/2″ UNC – 13 | – |
| 10 | M10 x 1.5 | – | 1/2″ UNC – 13 | – |
| 10.625 | M10 x 1.5 | – | – | – |
| 12 | M10 x 1.5 | – | 1/2″ UNC – 13 | – |
| 12.625 | M10 x 1.5 | – | – | – |
Table 2. Maximum Torque Figures for Standard ACL® Clamp Threaded Fasteners
| MAXIMUM TORQUE VALUES | ||
|---|---|---|
| BOLT SIZE | NM (DRY) | NM (LUBRICATED) |
| 5/16″ UNC – 18 | 11.2 | 10.05 |
| M8 x 1.25 | 21.57 | 19.09 |
| M10 x 1.5 | 42.17 | 37.85 |
| M12 x 1.75 | 73.55 | 65.08 |
| 1/2″ UNC | 92.7 | 83.15 |
Table 3. Torque Conversion Factors
| SI UNITS | IMPERIAL UNITS | METRIC UNITS | |||||
|---|---|---|---|---|---|---|---|
| UNITS TO BE CONVERTED | CN.M | N.M | OZF.IN | LBF.IN | LBF.FT | KGF.CM | KGF.M |
| 1cN.m = | 1 | 0.01 | 1.416 | 0.088 | 0.007 | 0.102 | 0.001 |
| 1 N.m = | 100 | 1 | 1.416 | 8.851 | 0.738 | 10.20 | 0.102 |
| 1ozf.in = | 0.706 | 0.007 | 1 | 0.0625 | 0.005 | 0.072 | 0.0007 |
| 1lbf.in = | 11.3 | 0.113 | 16 | 1 | 0.083 | 1.152 | 0.0115 |
| 1lbf.ft = | 135.6 | 1.356 | 192 | 12 | 1 | 13.83 | 0.138 |
| 1kgf.cm = | 9.807 | 0.098 | 13.89 | 0.868 | 0.072 | 1 | 0.01 |
| 1kgf.m = | 980.7 | 9.807 | 1389 | 86.8 | 7.233 | 100 | 1 |
Seals and Lubrication
Sanitary elastomeric seals have very good sealing capabilities and seal at a low clamping force. PTFE does not have these characteristics and the material creep even at low temperatures results in a decreased clamping force on the gasket which can produce a leak at a low pressure.
Lubrication has a noticeable effect on the pressure holding capability of the clamp unions, specifically when polymeric gaskets are used. Also, when the bolts are unlubricated there is an increased possibility that the threads will gall.
Lubricated clamp loads are 46% higher than dry loads. This will allow for higher force to be imparted onto the polymeric gasket, thus resulting in a more reliable seal.
For instance:
- A ½” UNC bolt lubricated and tightened to 83.15Nm will apply a clamping load of 1448 Kg. This load will utilise 90% of the bolt yield strength.
- A ½” UNC bolt un-lubricated and tightened to 92.7Nm will apply a clamping load of 772 Kg. This load will utilise 40% of the bolt yield strength.
In addition to this; as the torque figure is increased, the chances of galling and failure of the eyebolt at the thread root increase. In order to ensure a better lifetime for your acl clamp, torque should be minimised to the correct level.
In the event that lubrication cannot be applied to the threads, a suitable bolt /nut material combination should be employed. The standard material for this application would normally be Nitronic 60 (Ref. ACL® Anti-Gall).
All technical information and advice given here is based on our previous experiences and/or test results. We give this information to the best of our knowledge, but assume no legal responsibility. Customers are asked to check the suitability and usability in the specific application, since the performance of the product can only be judged when all necessary operating data are available. Specifications are subject to change without notice. ACL’s terms and conditions of sale apply to the purchase and sale of the product.
Sanitary elastomeric seals have very good sealing capabilities and seal at a low clamping force. PTFE does not have these characteristics and the material creep even at low temperatures results in a decreased clamping force on the gasket which can produce a leak at a low pressure.
Lubrication has a noticeable effect on the pressure holding capability of the clamp unions, specifically when polymeric gaskets are used. Also, when the bolts are unlubricated there is an increased possibility that the threads will gall.
Lubricated clamp loads are 46% higher than dry loads. This will allow for higher force to be imparted onto the polymeric gasket, thus resulting in a more reliable seal.
For instance:
- A ½” UNC bolt lubricated and tightened to 83.15Nm will apply a clamping load of 1448 Kg. This load will utilise 90% of the bolt yield strength.
- A ½” UNC bolt un-lubricated and tightened to 92.7Nm will apply a clamping load of 772 Kg. This load will utilise 40% of the bolt yield strength.
In addition to this; as the torque figure is increased, the chances of galling and failure of the eyebolt at the thread root increase. In order to ensure a better lifetime for your acl clamp, torque should be minimised to the correct level.
In the event that lubrication cannot be applied to the threads, a suitable bolt /nut material combination should be employed. The standard material for this application would normally be Nitronic 60 (Ref. ACL® Anti-Gall).
All technical information and advice given here is based on our previous experiences and/or test results. We give this information to the best of our knowledge, but assume no legal responsibility. Customers are asked to check the suitability and usability in the specific application, since the performance of the product can only be judged when all necessary operating data are available. Specifications are subject to change without notice. ACL’s terms and conditions of sale apply to the purchase and sale of the product.
Table 4. ACL® Clamp Torque Values – Elastomeric (Dry)
SH SSH ASME VIII S-TYPE NOMINAL SIZE (INCHES) FLANGE
SIZE MAWP TORQUE (NM) MAWP TORQUE (NM) MAWP TORQUE (NM) MAWP TORQUE (NM) 0.5 25 50 2 75 2 25 2 DN10 34 50 2 75 2 25 2 1.5 50.5 50 2 75 2 167 2 25 2 2 64 50 2 75 2 90 2 25 2 2.5 77.5 50 2 75 2 25 2 3 91 40 3 60 3 90 3 20 3 3.5 106 40 3 60 3 20 3 4 119 35 3 53 3 57 3 17 3 4.5 130 30 4 45 4 15 4 5 144.4 30 4 45 4 28 4 5.5 155 30 4 45 4 6 167 30 5 45 4 22 4 15 4 6.625 183 25 5 38 5 22 5 8 217.4 20 5 30 6 15 6 8.625 233.5 20 6 30 6 12 6 10 268.1 16 8 10 8 10.625 286.1 16 8 12 319 10 10 7 10 12.625 338 10 10
Note: Torque values for elastomeric union seals are given as a dry value. The torque value can be
kept to a minimum as elastomeric seals are self-energising. In the event that a seal is not achieved,
lubrication should be applied to the bolt or a higher torque should be used (do not exceed maximum
torque values shown in Table 2).
| SH | SSH | ASME VIII | S-TYPE | ||||||
|---|---|---|---|---|---|---|---|---|---|
| NOMINAL SIZE (INCHES) | FLANGE SIZE | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) |
| 0.5 | 25 | 50 | 2 | 75 | 2 | 25 | 2 | ||
| DN10 | 34 | 50 | 2 | 75 | 2 | 25 | 2 | ||
| 1.5 | 50.5 | 50 | 2 | 75 | 2 | 167 | 2 | 25 | 2 |
| 2 | 64 | 50 | 2 | 75 | 2 | 90 | 2 | 25 | 2 |
| 2.5 | 77.5 | 50 | 2 | 75 | 2 | 25 | 2 | ||
| 3 | 91 | 40 | 3 | 60 | 3 | 90 | 3 | 20 | 3 |
| 3.5 | 106 | 40 | 3 | 60 | 3 | 20 | 3 | ||
| 4 | 119 | 35 | 3 | 53 | 3 | 57 | 3 | 17 | 3 |
| 4.5 | 130 | 30 | 4 | 45 | 4 | 15 | 4 | ||
| 5 | 144.4 | 30 | 4 | 45 | 4 | 28 | 4 | ||
| 5.5 | 155 | 30 | 4 | 45 | 4 | ||||
| 6 | 167 | 30 | 5 | 45 | 4 | 22 | 4 | 15 | 4 |
| 6.625 | 183 | 25 | 5 | 38 | 5 | 22 | 5 | ||
| 8 | 217.4 | 20 | 5 | 30 | 6 | 15 | 6 | ||
| 8.625 | 233.5 | 20 | 6 | 30 | 6 | 12 | 6 | ||
| 10 | 268.1 | 16 | 8 | 10 | 8 | ||||
| 10.625 | 286.1 | 16 | 8 | ||||||
| 12 | 319 | 10 | 10 | 7 | 10 | ||||
| 12.625 | 338 | 10 | 10 |
Note: Torque values for elastomeric union seals are given as a dry value. The torque value can be
kept to a minimum as elastomeric seals are self-energising. In the event that a seal is not achieved,
lubrication should be applied to the bolt or a higher torque should be used (do not exceed maximum
torque values shown in Table 2).
Table 5. ACL® Clamp Torque Values – Polymeric (Lubricated)
SH SSH ASME VIII S-TYPE NOMINAL SIZE (INCHES) FLANGE
SIZE MAWP TORQUE (NM) MAWP TORQUE (NM) MAWP TORQUE (NM) MAWP TORQUE (NM) 0.5 25 50 6 75 6 25 6 DN10 34 50 6 75 6 25 6 1.5 50.5 50 6 75 6 167 10 25 6 2 64 50 6 75 6 90 10 25 6 2.5 77.5 50 6 75 6 25 6 3 91 40 9 60 9 90 15 20 9 3.5 106 40 9 60 9 20 9 4 119 35 9 53 9 57 15 17 9 4.5 130 30 10 45 12 10 10 5 144.4 30 10 45 20 28 20 5.5 155 30 16 45 20 6 167 30 20 45 20 22 20 7 10 6.625 183 25 20 38 25 22 25 8 217.4 20 20 30 30 15 24 8.625 233.5 20 24 30 30 12 24 10 268.1 16 32 10 32 10.625 286.1 16 32 12 319 10 37.5 7 40 12.625 338 10 37.5
Note: Torque values for polymeric union seals are given as a lubricated value. In the event that a seal
is not achieved, lubrication should be re-applied to the bolt or a higher torque should be used (do not
exceed maximum torque values shown in Table 2).
| SH | SSH | ASME VIII | S-TYPE | ||||||
|---|---|---|---|---|---|---|---|---|---|
| NOMINAL SIZE (INCHES) | FLANGE SIZE | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) | MAWP | TORQUE (NM) |
| 0.5 | 25 | 50 | 6 | 75 | 6 | 25 | 6 | ||
| DN10 | 34 | 50 | 6 | 75 | 6 | 25 | 6 | ||
| 1.5 | 50.5 | 50 | 6 | 75 | 6 | 167 | 10 | 25 | 6 |
| 2 | 64 | 50 | 6 | 75 | 6 | 90 | 10 | 25 | 6 |
| 2.5 | 77.5 | 50 | 6 | 75 | 6 | 25 | 6 | ||
| 3 | 91 | 40 | 9 | 60 | 9 | 90 | 15 | 20 | 9 |
| 3.5 | 106 | 40 | 9 | 60 | 9 | 20 | 9 | ||
| 4 | 119 | 35 | 9 | 53 | 9 | 57 | 15 | 17 | 9 |
| 4.5 | 130 | 30 | 10 | 45 | 12 | 10 | 10 | ||
| 5 | 144.4 | 30 | 10 | 45 | 20 | 28 | 20 | ||
| 5.5 | 155 | 30 | 16 | 45 | 20 | ||||
| 6 | 167 | 30 | 20 | 45 | 20 | 22 | 20 | 7 | 10 |
| 6.625 | 183 | 25 | 20 | 38 | 25 | 22 | 25 | ||
| 8 | 217.4 | 20 | 20 | 30 | 30 | 15 | 24 | ||
| 8.625 | 233.5 | 20 | 24 | 30 | 30 | 12 | 24 | ||
| 10 | 268.1 | 16 | 32 | 10 | 32 | ||||
| 10.625 | 286.1 | 16 | 32 | ||||||
| 12 | 319 | 10 | 37.5 | 7 | 40 | ||||
| 12.625 | 338 | 10 | 37.5 |
Note: Torque values for polymeric union seals are given as a lubricated value. In the event that a seal
is not achieved, lubrication should be re-applied to the bolt or a higher torque should be used (do not
exceed maximum torque values shown in Table 2).