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  1. gmorin

    N2 purge during PWHT

    I have a carbon steel pipe component (B31.3) that I need to PWHT because of a sour service requirement. All of our past projects have not had the PWHT requirement. This component has a critical interior surface finish, so I need to limit corrosion as much as I can, such that any rust that had...
  2. gmorin

    double random pipe availability

    Sizes I was looking for on this project were: - 1-1/4” Sch. 80 (I wasn't surprised by this one) - 3” Sch. 80 (I was able to find this one) - 1” Sch. 160 (This one surprised me) All in A106 Carbon steel I'm buying small quantities 250 ft or less on each - maybe that's the problem, but this is...
  3. gmorin

    double random pipe availability

    The unit I'm designing requires a minimum number of welds and therefore there is a strong preference for double random (40 ft - 12m) nominal piping. I'm talking pipe sizes 1"-4" - some in schedules other than STD or XS. My projects can be fabbed in the US, Korea or Europe. Over the past...
  4. gmorin

    Calcium silicate insulation - minimum thickness

    I'm using cal sil insulation on a refinery project. The client's insulation table and a couple vendor websites have indicated that 25mm (1") thick cal sil is available, but some of my colleagues are questioning whether it'd be too fragile. They were concerned it may be tough to work with and...
  5. gmorin

    Belleville washer in hot service

    I have an externally generated requirement to provide belleville (spring loaded) washers in my piping system. I haven't used them in the past, but passed along the requirement to my subvendors. (B31.3 piping - hydrogen service) I have a supplier who's objecting to providing them on the grounds...
  6. gmorin

    Preinsulated Piping Corrosion

    For insulation, look into cellular glass, like stanier suggests. It doesn't absorb water & stays on the pipe if it does get wet. One mfr: http://www.foamglasinsulation.com/ I'm sure you'll get some horror stories posted here, but a steel sleeve pipe would be my default choice. It would...
  7. gmorin

    How to specified pressure drop for orifice and control valve sizing

    Keep in mind that the pressure drop across a control valve is generally dicated by the upstream and downstream pressures, not vice versa. Unless your pressure source and user are also being designed as part of your project, the pressure drop across your valve / orifice system will be your...
  8. gmorin

    Selection of pipe going fron river to cooling tower.

    It depends on the diameter and distance you're going, as well as your water quality. If you're 4" to 20" in diameter and underground, HDPE is probably the best choice. It's corrosion resistant and cheap to install if you have an experienced installer with the right equipment. I assume you'll...
  9. gmorin

    Flow through flow control valve - how to read it?

    75 psi going to 5 psi is definitely choked flow. Remember to use absolute units (unless you are and the 5 psi is a vacuum system) This simplifies the flow "measurement" - you don't need to be concerned about the downstream pressure. Is this an on-off application or a modulating control...
  10. gmorin

    P&ID Symbology

    Yep. The problem is that too many companies, in too many industries have been doing P&ID's for too long. My (100 yr old) company is part of the problem - we have some weird symbols in our standards that I haven't seen elsewhere in the power industry.
  11. gmorin

    Flow through flow control valve - how to read it?

    Please note all of the warnings above. If you're looking for any kind of accuracy, get a flowmeter. I've used the following correlation with reasonable results. It's better than the water correlations, anyway. I'm not sure of the ultimate source - I'm getting it out of the back of a valve...
  12. gmorin

    P&ID Symbology

    I ran into this issue from the other end. I'm on a project where I'm designing the balance of plant scope on a large pollution control project. My client asked my company (an A/E) and the major equipment supplier for the project to use the same symbology on our diagrams. We both claimed to...
  13. gmorin

    Exposed copper (for water) OK in industrial building?

    Agreed. We use copper for some clients. Be advised, however, that I've had more than one contractor provide a zero cost option to use socket weld schedule 10S stainless for air systems instead of copper (power plant applications). They apparently prefered a stainless socket weld to a solder...
  14. gmorin

    Pipe Support for motor operated valve

    Supporting an MOV off a small bore line is a hassle -especially if there's any thermal expansion to speak of, but it's well worth it.
  15. gmorin

    Hot water bypass valve

    I've seen that arrangement in a greenhouse application before. It is good for heating applications where you don't want to have on-off swings in your heater temperature. Basically, if your temperature is at set point, the water is recirculated through your jacket and you don't consume any hot...
  16. gmorin

    What is a "pegging steam" in the HRSG deaerator ?

    Pardon the repetition with the previous, but I think I have something to add: You need to consider the HRSG deaerator like a regular boiler's deaerator. It's an open cycle feedwater heater which brings the feedwater up to saturation before it goes through the feedwater pump. It needs a...
  17. gmorin

    Sulphuric acid piping

    Note that material selection is highly dependant upon the acid concentration - sometimes in counter-intuitive ways. I'd be careful using carbon steel. If you do so, note that the Sch 80 piping suggested above is a corrosion allowance and you will lose material every year. The conservative...
  18. gmorin

    Alternative Slide Support?

    Is the w8 building steel or is it aux steel installed specifically for this application? If the w8 can be moved down relative to the pipe, then you could replace the shoe with a base clamp type design (One manufacturer is Lisega (type 49) - www.lisega.com). The pipe would then be far enough...
  19. gmorin

    High Density Polyethylene pipe transition

    We generally try to transition above ground. When you're installing HDPE for its corrosion properties, it makes some sense to avoid an underground metal pipe transition. Note that unlike a lot of other HDPE users, we also generally specify flanged transitions instead of mechanical joints...
  20. gmorin

    Warm-Up Rates for Steam Systems

    Generally your warmup rate is limited by your traps, orifices, and/or vent valves. If the line is properly designed and you have traps or orifices, I can't see any way that you could get into trouble by heating your line too fast. Large vent valves would be more likely to get you into trouble...
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