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@r6155 It's well understood that when you "plug" a repad vent hole/TTH with stiff grease that you're not actually plugging it to retain pressure. The reason you plug/fill the repad vent hole with stiff grease after fabrication is to prevent moisture ingress & local corrosion of the vent hole...

Forgot to mention, the reason for this vent hole in repad (in case it isn't clear) is to allow any welding vapors for the repad to vent out & not become trapped within the shell/nozzle area enclosed by the repad

The breathing/vent hole in repad is typically tapped with threads to do a 15 psig air test on the repad weld. Just plug the tapped vent hole with stiff grease (after painting, if req'd).

You need to specify the pipe schedule bore when ordering socket weld flanges, similar (but not exactly the same) to weld neck flanges. Otherwise you'll like end up with mismatched bores/IDs btw flange & pipe. Typically socket weld flanges are used in small bore applications (<2" size). Small...

When specifying tube-to-tubesheet strength welds, I've typically gone with & seen the Fig UW-20.1(b) joint design the most. But it can depend on you're design conditions. This is a groove weld with the tubesheet holes beveled. The size of your groove weld legs is determined under UW-20.6...

Typically you're design conditions on heater tubes are fairly low pressure, high temperature. Performing a hydrotest to API530 (1.5 x DP x Stress Ratio) is usually pretty feasible, unless your coils have older/existing plug header returns (instead of typical 180deg return bend fittings). The...

Ah, welcome to Pandora's Box....When you ask about Belzona, you must be specific on which Belzona product. There are dozens of types. Typically, when people say "Belzona", they're referring to an epoxy type coating (typically internal coating) used for corrosion protection. However, Belzona...

Just use a LWN nozzle (self reinforced). Never seen a vessel nozzle gusseted before. As GD2 stated, you typically only see gusset braces on small bore piping branches (under B31.3), and often it's designed & installed poorly. Nozzle repads at high design temps also have drawbacks with...

Curious forum's opinions or experiences on this...I work at a refinery with an HF Alky unit. We've had many HF acid leaks in past with valve bolted bonnets, particularly with small bore gate valves. I would like to change to welded bonnet (threaded & seal-welded) style small bore gate valves...

A. Correct B. Only an Oval Ring type gasket can be used with Oval groove RTJ flanges

One common issue with carbon steel RTJ flanges is the material of ring gasket used. What is your ring gasket material? I'd recommend Soft Iron ring gaskets only for carbon steel RTJ flanges, as your ring gasket hardness must be lower than your RTJ flange hardness to effect a good seal. I've...

Why would you have a 1500# flange in a system with such a low design pressure & temperature? What is the size of flange?

NPT threads on flex hose ends at 1200F? May want to consider changing those to flanged end connections & use a high temp gasket.

@ r6155 You are the confused one. Chapter IX of B31.3 applies to High Pressure piping (>2500# design pressures) only. In this case we are talking standard Category D & Normal fluid services with a design pressure of only ~90 psig (6 bar). Socket weld fittings are both acceptable by code &...

Any competent site contractor will tell you it's much easier to socket weld 1/2" - 1-1/2" size pipe with quality compared to buttwelding pipe in this size range. From a purist engineer perspective, you can't beat buttwelds. But the reality is ensuring a min 1/16" socket gap prior to socket...

If you can smart pig these tubes to check for wall thicknesses & ovality/creep bulging, that will help a bunch. Furnace tubes can take a great deal of sagging before they fail an API579 FFS Level 3. However, if the tubes are creep bulged (radial growth on ID and/or OD) above 3% or so of...

Danlap - Yes this is for high viscosity & high temp application (asphalt/resid hydrocarbons operating btw 500 - 600 degF [260 - 315 degC]). We do not use a root valve (block before before sampling valve) either for reasons you mentioned. We often install a 1/2" globe valve on the sampling valve...

Yep, I've tried there. They direct me to my local regional rep, who is unresponsive.

Curious forum's opinion on minimum girth weld & branch weld spacing requirements on new piping & modified existing piping (B31.3 code)? Most companies have best practices/standards that define minimum weld spacing clearances for girth & branch welds for new piping. However, I'm not 100% sure...

Does forum have any experience ordering Strahman sampling valves? I am needing to order replacement ones for downstream/petrochem applications. I am not having any luck contacting Strahman & getting ahold of anyone. Also, is forum aware if any competitor products that exist for these...