Finding ASME B16.5 Blind Flange Bolt Load
Having a difficult time figuring out the Bolt Load (W) for your modified ASME B16.5 blind flange? Check the flange it is attached to!
Oftentimes ASME B16.5 blind flanges used as reducers include pipes larger than allowed in B16.5 without a reinforcement calculation. I have found that the additional bolted cover calculation trips up some designers as they were expecting the ASME B16.5 blind flange to be exempt. The most common reason people reach out to me is for help finding the Bolt Load (W) needed in the bolted cover required thickness calculation.
Please remember that mating pairs share the Bolt Load (W). This means that finding the Bolt Load (W) needed for the bolted cover required thickness calculation may be as simple as grabbing it from the flange it is attached to.
Outdated Nuclear Industry
Nuclear, I get it. You are trying to go fast. But please be like the rest of the world and consider designing with the latest Codes and Standards.
Yes, you can technically use that same 1970’s heat exchanger design in your brand new plant, but why would you want to? New designs will perform better and last longer because they incorporate the latest design rules with M-Star CFD and modern manufacturing techniques.
Did you know that your old heat exchanger designs pre-date the UHX rules? I’ve seen 𝐜𝐫𝐚𝐳𝐲 𝐭𝐮𝐛𝐞 𝐬𝐭𝐫𝐞𝐬𝐬𝐞𝐬 in fixed exchangers because the old design never checked for tube stress. I’ve seen 𝐞𝐱𝐭𝐞𝐫𝐧𝐚𝐥 𝐩𝐫𝐞𝐬𝐬𝐮𝐫𝐞 𝐧𝐨𝐭 𝐜𝐨𝐧𝐬𝐢𝐝𝐞𝐫𝐞𝐝 in floating tubesheet exchangers when it should have governed the maximum shell side pressure. I’ve seen nozzles 𝐭𝐨𝐨 𝐜𝐥𝐨𝐬𝐞 𝐭𝐨 𝐭𝐡𝐞 𝐭𝐮𝐛𝐞𝐬𝐡𝐞𝐞𝐭 in u-tube exchangers which should have failed UHX-4(i)(1).
Going fast doesn’t have to mean using your old, bad designs. Unsure about your old design drawings and calculations? Metalmark Engineering offers 3rd party view to give your team peace of mind while going fast.
AI Generated FEA Results
The era of AI generated FEA results is here!
I like comparing FEA results to closed-form solutions because they help validate each other.
I 𝐥𝐨𝐯𝐞 comparing AI generated FEA results to closed-form solutions because they give me a good laugh.
Thankfully the trend of getting AI generated FEA results through regulators appears to be over. In Canada Annex J of CSA B51 spells out the exact requirements regarding using FEA in equipment design. A couple of effective requirements stand out to me.
J.2) FEA may be used to support equipment design where the configuration is not covered by the available rules.
Many times AI generated FEA is submitted for simple designs already covered by ASME Division 1 and Division 2. This rule prevents FEA-only submissions for simple designs.
J.3) FEA report shall be certified by a Professional Engineer
The entire point of creating AI generated FEA results is to circumvent engineering costs. This rule prevents submissions from unqualified actors putting the public at undue risk.
While your regulatory jurisdiction may not have any requirements regarding the use of FEA, I strongly support considering these two requirements for internal rules. Please be careful when selecting a fly-by-night unlicensed FEA firm with pricing that is too good to be true.
Mixing Units in Drawings Rejected by Regulators
Don’t let this simple mistake cause your design drawings to be rejected by regulators.
Modern design drawings often use US Customary and metric units interchangeably. Not a big deal for experienced designers and fabricators that are used to seeing both. However, there are a few specific cases I look for because I’ve seen them rejected by regulators.
One of those is when 6mm fillet welds are applied to ¼” nozzle reinforcement pads. A 6mm weld works on a 6mm plate. A 6mm weld does not work on a ¼” plate due to the UW-16(d) weld size check. The difference between 6mm and 6.35mm may seem trivial to fabricators but it is not trivial to regulators who check design drawings for this specific combination.
Did you know that 3rd party reviews help you execute projects faster? Metalmark Engineering checks your design drawings against your design calculations to give you the best chance to sail through regulatory review.
Use Closed-Form Solutions Instead of Bad FEA Calculations
Are you wasting money on bad FEA calculations that won’t make it past regulators?
I was recently asked to help a client review some calculations that were rejected by a prominent regulator in the industry. After ogling some aesthetically gorgeous FEA pictures I had the same question as the regulator:
“Why are you using FEA?”
The nozzle geometry was pretty basic. A 12”, set-in, radial nozzle with a reinforcing pad.
Not in cyclic service. No crazy thermal gradients. No external loads. No reason for an FEA only calculation submission.
What should have been a five dollar closed-form solution calculation turned into an expensive FEA nightmare. Please consider using closed-form solutions for designs where the configuration is fully covered by the available ASME rules.
Seamless Pipe with PWHT Designation
A Post Weld Heat Treatment (PWHT) designation for Seamless Pipe? Is that crazy?
It may not be standard procedure, but it isn’t crazy. I like to specify PWHT for seamless pipe materials when the pipe specification service calls for PWHT.
Let’s take a look at a common scenario where calling out Post Weld Heat Treatment (PWHT) designation for Seamless Pipe could have saved a big headache. In the example picture a new circuit was added to an existing circuit with a required PWHT designation due to service requirements. Since the seamless pipe did not have a PWHT designation, the welded pipe added during an expansion did not receive the required post weld heat treatment. The new pipe section that did not receive PWHT quickly experienced in-service issues.
Undocumented Equipment
Missing your name plate? Even worse, are you missing your design calculations?
No documentation? No problem!
I’m often asked questions about undocumented equipment when I’m on site for turnarounds. Owner/Operators would like to return undocumented equipment back to service but they do not have an engineering department with enough time to handle the complexities involved. Material identification, measuring dimensions and thicknesses, performing internal and external inspections, and providing detailed calculations adds way too much workload to think about handling undocumented equipment internally.
So it sits…and sits...
Sure, not all undocumented equipment is suitable to return to service, but wouldn’t you like to find out?
Metalmark Engineering helps you stay on top of OSHA’s Process Safety Management (PSM) program by providing missing design calculations, inspection reports, and detailed design drawings for your equipment without documentation.
Add Corrosion Allowance in Steam Service
Zero corrosion allowance for steam service? When did this design become normal?
Many times I see steam service equipment designed with a 0.25” (6 mm) nominal thickness and zero corrosion allowance. This occurs because steam service is often included in the lowest Risk Category in plants. Low Risk Category equipment will inherently have a zero corrosion allowance requirement. I’ve reviewed enough internal inspection reports for equipment in steam service to conclude that steam can be corrosive, especially in bottom head components.
Not including a corrosion allowance in the original design calculations often leads to dangerously thin components when real-world conditions eat through the zero corrosion assumption. Please reconsider designing with zero corrosion allowance for equipment in steam service.
Expensive Hydrotests
Sometimes performing the ASME Code required hydrotest is deemed too expensive so Owner/Operators skip it.
One factor that may raise the cost of hydrotesting is if the hydrotest pressure is much greater than the operating pressure. The higher hydrotest pressure may require the fabrication of single-use components, supplying a special set of gaskets, and another PCC-1 Appendix O calculation.
One of the sad realities of the extreme cost-cutting associated with modern manufacturing is the loss of basic design principles. I’ve noticed that performing proof tests and leak tests instead of ASME Code required hydrotests is becoming increasingly popular in new vessel construction.
Authorized Inspectors (AIs) often assume a shop hydrotest was performed and never check the U-Form notes that clearly states otherwise. The “what can I get away with?” mentality rewards design engineers with promotions while operator roles become increasingly dangerous.
ASME PCC-1 Appendix O
ASME PCC-1 Appendix O has a lot of stress values to look up (or calculate) and using “defaults” isn’t going to help you solve real world problems. Over the next few weeks I’ll be going over where to get some of the stress values you will need in order to properly determine bolt torque values using ASME PCC-1 Appendix O.
Maximum Permissible Bolt Stress, Sbmax
Minimum Permissible Bolt Stress, Sbmin
Target Assembly Gasket Stress, SgT
Maximum Permissible Gasket Stress, Sgmax
Minimum Operating Gasket Stress, Sgmin-O
Minimum Seating Gasket Stress, Sgmin-S
Assembly Bolt Stress, Sbsel
Wait, just seven stress values? That seems way too easy! It is! But let’s start here and save the Maximum Permissible Bolt Stress for the Flange, Sfmax determination calculation using WRC 538 for after your exam.
Stop Designing with Deadlegs
Are you unintentionally adding deadlegs to your piping designs?
We all have hopes and dreams but your "future expansion” may actually be a major hazard due to the susceptibility of corrosion in these areas. Please be careful with piping headers and branched connections that are intentionally blinded off after construction to prepare for a future expansion. Many times the expansion plan never materializes and the associated deadleg is never properly accounted for in the site’s integrity program.
What’s wrong with deadlegs? They get hardly any flow and experience higher corrosion rates than the rest of the piping system.
CMLs Showing Equipment Growth
Ever plot CML thickness and notice your piping or equipment growing over time?
This “reverse corrosion” phenomenon sweeping inspection departments can defile your data and give false impressions of real metal loss and corrosion rates.
How common are growth readings for CMLs? VERY. In fact, during Jeff Goldstein, P.E.’s latest webinar “Rethinking Piping Inspection Locations” he discussed a site with 12,000 of 40,000 CML readings showing growth over the last CML reading. That is 30% of readings showing a growth rate instead of an expected metal loss/corrosion rate. What you decide to do with these growth readings will have a big impact on maintenance and inspection plans moving forward.
Maybe there was an undocumented piping or equipment replacement.
Maybe the measuring device was not properly calibrated when the operator took CML readings.
Maybe the CML readings were entered into software or spreadsheets incorrectly.
Maybe the CML readings were taken in the wrong location.
Please spend some time trying to understand what is causing growth readings and act accordingly.
Storage Tanks Floating During Storms
Have you ever seen an API 650 storage tank sail away during a storm?
As August progresses and the risk of hurricanes increases so does the risk of a storm surge turning your storage tanks into sailboats. Please consider the risk of a storm surge on your tanks before it happens.
One great option is to fill the tanks enough to prevent them from becoming buoyant in the first place. Filling the tank with product, similar products, or even water can add enough weight to prevent tanks from floating away. Please consider the downstream effects of each before selecting the fill option that is best for you and make a plan before the storm comes.
Another option is to use shell anchorage to prevent the tank from floating when it becomes buoyant. Make sure you incorporate shell anchorage into the original design if this option is used. COMPRESS makes this easy by putting the shell anchorage option directly into the tank dialog. Keep in mind that anchorage alone may not completely prevent failure of the tank bottom when it becomes buoyant as high stresses can occur at the shell-to-anchorage intersection.
Special thanks to Carlos F Molina for sharing so much of his tank experience with me. Check out his APIExam newsletter for more in-depth information regarding API 510, API 650, and API 653 and how to pass the exams!
Internal Nozzle Area
Can you use internal nozzle area to pass UG-37 area-of-replacement requirements?
Yes, you can!
Any area within the limits of reinforcement counts as area towards the UG-37 area-of-replacement requirements, including internal nozzle area. Adding an internal nozzle projection is a way some designers meet the area-of-replacement rules when they need a little extra reinforcement.
However, make sure that the process department for your Owner/Operator is okay with using internal nozzle projection in your designs before going forward. Some specification sheets allow internal projection for inlet nozzles but not for outlet nozzles. Others do not allow internal projection at all!
B16.5 Blind Flanges as Reducers
Ever see ASME B16.5 blind flanges as reducers?
Just throw any pipe in a standard ASME B16.5 blind and you’re good-to-go, right?
No. That “standard” ASME B16.5 blind flange may not be “standard” once you decide to start drilling holes in it. Many times ASME B16.5 blind flanges used as reducers include pipes larger than allowed in B16.5 without a reinforcement calculation. Please make sure your facility has proper documentation for ASME B16.5 blind flanges used as reducers.
Add Stairs to API 650 Tanks
Did you know you can add stairs directly to your API 650 tank design in COMPRESS?
I enjoy telling myself “I’m not that old” but tank ladders provide real-world cases to prove otherwise. Providing stair access to new API 650 storage tanks is an inexpensive way for Owner/Operators to boost morale and improve safety at their tank farms.
I prefer to add stairs during the design phase because the additional weight can have a big impact on calculations.
Verify Thicknesses Before Installing Equipment
Do you verify thicknesses before receiving your equipment?
The design calculations use NPS 8 Sch 120.
The fabrication drawings use NPS 8 Sch 120.
You received NPS 8 Sch 80 (XS).
So what happened? A drawing was misinterpreted and a fabrication mistake was made. Fabrication mistakes happen. Don’t compound those mistakes by not finding them until after installation. Using a 3rd party to verify that your as-built thicknesses meet or exceed your design thicknesses is a quick and important step you should implement before receiving your equipment to help improve your bottom line.
I like to use 3rd parties for thickness verification because they are excellent at communicating between fabricators and Owner/Operators during stressful projects. I trust Turnaround EPC for my 3rd party as-built thickness verification because of their excellent communication, fast service, and attention to detail.
Use ASME PCC-1 Appendix O to Fix Leaky Gaskets
Do you have an issue with leaky gaskets?
A lot of people message me complaining about leaky flange gaskets and wondering what kind of gaskets I recommend to help. The fact of the matter is that gasket quality and performance has never been better. I have found that many times the real problem is that the gasket was not considered during the design phase. Gaskets are an important part of flange design. Treat them that way.
Have you performed ASME PCC-1 Appendix O for your flanges?
An approach in ASME PCC-1 Appendix O can help you make sure your gaskets are being seated correctly. The gasket needs to be below the maximum permissible gasket stress, above the minimum seating gasket stress, and above the minimum gasket operating stress. In this example the minimum gasket operating stress is not being maintained at the operating condition.
Make sure you perform ASME PCC-1 next time you open up a pair of flanges.
Consider Longitudinal Stresses in Brittle Fracture Check
Do you consider longitudinal stresses when you check for brittle fracture?
I’ve had a lot of people asking me to check their hydrotest temperatures. A design where a governing longitudinal stress case was not considered in the Minimum Design Metal Temperature (MDMT) stood out to me.
Did you know that longitudinal stresses can govern the MDMT even if circumferential stresses govern the Maximum Allowable Working Pressure (MAWP)? Not checking the longitudinal stresses can lead to devastating results as the brittle mode of failure is swift and catastrophic. Always remember to consider longitudinal stresses in your brittle fracture check.
Move Data from U-Forms into Spreadsheets for AI
Are you ready for AI? Your data is not.
One of the big themes of Reuters Downstream 2025 was the use of AI in maintenance and inspection. I found the concept of using AI for predictive analytics in maintenance incredibly intriguing. However, let’s not pretend that your important data is in a format that AI can actually use. You need to digitize your data.
Are your U-Forms sitting in a filing cabinet somewhere?
How about the historical measured thickness data from internal inspections? Are those values just floating around in PDFs?
What about the interesting information found during external inspections? Repairs? Rerates? Derates? FFS assessments? Wouldn’t you want all of that data digitized in a way that makes it easy for AI to pull from?
We all know that AI is the future but AI is only as good as the data you are feeding it. Consider yourself behind if the items listed above are not in a usable, digital format.