WASHER MATERIAL

[bayardwv]

What is the best way to determine what specification/s a washer needs to adhere to on an ASME Section VIII, Div.1 pressure vessel?
Is there anywhere in Section VIII, Div.1 stating carbon steel washers SHALL be made from material listed in Table UCS-23 or Section II materials?
The washer isn't being used on a traditional B16.5/47 Flange design, but instead a custom swingbolt design where the Bolt Circle is larger than the OD of the Flange and the washer is spanning the gap between the Clip Legs. I've attached a picture for reference.
My understanding is that this washer does not require pressure or strength calculations and the only material requirement is that they be made from Wrought Material, per UG-13.
UCS-11 states washers MAY be made from materials in Table II, not SHALL.
Does UCS-5 over-ride UG-13 and UCS-11?

Would calling for the washer be supplied in accordance with either ASTM F844 or F436 be sufficient?

 

[SnTMan]

bayardwv, without chasing thru all the refereces you provided, I'll just say F436 washers are commonly used in PV work. F844 appears to be unhardened, I'd think F436 (hardened) to be preferred.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[XL83NL]

Review ASME PCC1. Recommendations for washers are in there.

 

[MJCronin]

The topic of washers on ASME PV steel flanges has been discussed several times on these fora ...

Washers are NOT always required for steel flanges ....

MJCronin
Sr. Process Engineer

 

[Krausen]

Stick with F436 steel washers

Tolerance is the virtue of the man without convictions -GK Chesterton

 

[XL83NL]

Stick with F436 steel washers

I wouldnt recommend that. If you really need washers, make sure to understand ASME PCC-1, especially appendix M, M-1.4:

M-1.4 Existing Standards
Washers in accordance with ASTM F436 have been used
previously on piping flanges. However, the use of ASTM
F436 washers may lead to interference with the spot face/
back facing on the flanges. Also, ASTM F436 does not
provide dimensions for certain nominal sizes needed
for pipe or vessel flanges. The intent of the Type 1
washer in this Appendix is to specify a washer of the
same general material as an ASTM F436 washer but
with revised dimensions to make them compatible
with pipe or vessel flanges.

 

[r6155]

Washer is required for swing bolt closure.

Regards

 

[bayardwv]

My original post included an attachment showing the Swingbolt design.
This design requires a washer to provide a surface for the Nut to seat against.
Very Similar to a Tube Turns T-Bolt Closure.

I've been questioned why we aren't providing washers made from materials listed in tables UCS-23 or UHA-23 AS NOTED IN UCS-11.
My reply was because this paragraph says MAY be made from, not SHALL be made from. In addition I noted that per UG-13 the use of washers is optional and when used SHALL be made from wrought material.

Then I was told that because the washer was subject to stress due to pressure it is a pressure retaining part and must comply with UCS-5(a, regardless of what UG-13 & UCS-11 states.

I'm just trying to determine how this hasn't been questioned for the last 40+ years, and now it's a problem.

 

[r6155]

Use Extra Thick washer as per ASTM F 436.

Regards

 

[r6155]

In your design bolts are tensioned by hand and I understand you use O´ring gasket.

Regards

 

[SnTMan]

bayardwv, it is because the common sense that used to be widespread in the industry is being replaced by a legalistic frame of mind where every possible situation has to be covered in writing somewhwere. In my opinion.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Krausen]

"I wouldnt recommend that. If you really need washers, make sure to understand ASME PCC-1, especially appendix M, M-1.4:


Quote:

M-1.4 Existing Standards
Washers in accordance with ASTM F436 have been used
previously on piping flanges. However, the use of ASTM
F436 washers may lead to interference with the spot face/
back facing on the flanges. Also, ASTM F436 does not
provide dimensions for certain nominal sizes needed
for pipe or vessel flanges. The intent of the Type 1
washer in this Appendix is to specify a washer of the
same general material as an ASTM F436 washer but
with revised dimensions to make them compatible
with pipe or vessel flanges."

What would you recommend then? I think you're overthinking this.

First off, if a flange is spot faced or back faced then a washer really isn't needed. The whole point of the washer is to provide this smooth back face on a flange that doesn't have it.

Second, I've never once ran into an issue of F436 washers not having the correct dimensions to go with the required bolting of same nominal size. These dimensions are outlined in F436. Not saying this isn't some remote possibility out there, but this is definitely an exception to the rule.

Stick with F436 washers 99.999% of the time & move on...

 

[XL83NL]

Youre right. I’ve incorrectly read the OP’s first and wasn’t aware of the swingbolt. Sorry for the confusion.

 

[r6155]

Please, see the picture attached by (OP)

Swing-Bolt Closures consist of an ellipsoidal cap hinged to a hub.
Heat treated, high strength eye bolts, pinned to lugs on the hub,

Hence, washer is required.

Regards