NovaStark
Mechanical
- Feb 11, 2013
- 257
Good day all,
My facility has recently discovered a leak on a flange in H2 service so of course, fire.
I did notice however that insulation was wrapped around the entire valve body as well as the flanges on both ends.
Now while the design has called for insulation on the entire line (they didn't specify on the valve or at least didn't clearly state to not insulate it) I have been reading up on the insulation around bolted joints. Unfortunately I haven't found any hard design criteria stating whether or not to insulate bolted joints. Some people say to not due to high temperatures means that bolts lose tensile strength and thus the clamping force decreases whilst others say to insulate for heat conservation or personnel protection.
In the case of this leaking flange, it is up in the air so it is most likely for heat conservation. Anyone have any experience with the design for these joints with respect to thermal loading ?
Additional info. all components are stainless steel and the bolts are B16 bolts. (on another plant, same exact valve/flange ,etc. we have B7 bolts and I believe no insulation - this flange used to leak often and they removed the insulation and put B7 bolts so as to not have the bolts lose tension).
My facility has recently discovered a leak on a flange in H2 service so of course, fire.
I did notice however that insulation was wrapped around the entire valve body as well as the flanges on both ends.
Now while the design has called for insulation on the entire line (they didn't specify on the valve or at least didn't clearly state to not insulate it) I have been reading up on the insulation around bolted joints. Unfortunately I haven't found any hard design criteria stating whether or not to insulate bolted joints. Some people say to not due to high temperatures means that bolts lose tensile strength and thus the clamping force decreases whilst others say to insulate for heat conservation or personnel protection.
In the case of this leaking flange, it is up in the air so it is most likely for heat conservation. Anyone have any experience with the design for these joints with respect to thermal loading ?
Additional info. all components are stainless steel and the bolts are B16 bolts. (on another plant, same exact valve/flange ,etc. we have B7 bolts and I believe no insulation - this flange used to leak often and they removed the insulation and put B7 bolts so as to not have the bolts lose tension).
