[knives]

I’ve been seeing this requirement also from recent Project I worked with. What I remember though was it is only implemented during detail engineering stage (before issue for construction P&ID) as most FEED and basic engineering activities would still involves lot of changes in process design that could probably mess up some sequencing of tags.

[knives]

Thanks Mr. Anton. If you wont mind, could you also provide details on industry norms for the BOQ measurements. I know that it varies from one EPC contractor to another due to construction culture differences but it is very interesting to know how the quantities are presented in BOQs. For example, the pressure test work volume would be prepared and generally quantified in cu.m but others would prefer it on linear meter length per size, pipe support in no. of pcs instead of tonnage, Radiographic test in terms of no. of films instead of quantity of joint per size, etc.

[knives]

I would like to move this topic up to share some additional points

When modularizing a unit, some decision has to be made whether an equipment should be either included or taken off-module. Some of these considerations are:

(1) Large/heavy static equipment with very few and simple connections need to be taken out. They better be installed directly on site (ex. Large Compressor Surge Drums, Mol sieve beds, etc)

(2) Long lead equipment that could impact module fabrication schedule like all other module activities can’t proceed without that certain equipment should also be taken out. Assembly programme should be effective and should be de-risked by avoiding equipment with delivery schedule very near the module critical path.

(3) Tall vessels should be confirmed on a case by case basis. These vessels are also normally categorized as long lead equipment and requires a large crane at module fabrication shop to install within module. They also need to be supported with more steelwork and sea fastenings which contributes to the increase of weight and location of module center of gravity.

(4) Consider pumps to be off-module and utilize the height difference between ground and module deck (if the source is included in the modularisation) to improve pump NPSH. Providing a dedicated concrete foundation would also give a more effective vibration dampening solution. Small and medium sized pumps can be installed inside the module provided they are not on hydracarbon service which restricts to place the pump within the primary module frame (similar to stick-built type construction).

(5) Similar to pumps, compressor is better be placed outside the module unless the duty is exceptionally small.

(6) Heat exchangers (S&T type or similar) should be included in modules where they are
part of the contained process. However, exchanger connections are fairly simple and where
there are individual heat exchangers associated with stick-built or dressed columns,
modularisation benefits should be carefully evaluated.

(7) Where the size and/or arrangement of the AFCs compared with the module makes it impractical to complete the assembly in module fabrication shop, consider lifting the AFC onto the module in the site.

Also when designing a pipe route, the designer should take extra care that the route is clear from installation – both permanent and temporary such as SPMTs, transport packing, lifting eyes, slings, spreader beams and temporary sea fastenings.

[knives]

Thanks Jop, I agree that this type of support should not be place where grating removal is expected so I guess if ever this type of support is applied, the criteria should be agree with the owner and clearly indicated in support standard drawing. One of the reason I would like to keep this an option for our project is to reduce welding and touch-up paint work for any supplemental beam that may be needed to provide support point for base support above structure, We are also trying to manage the weight to as light as possible because the unit is modularised and additional structural beam here and there would definitely contribute to the increase of module weight.

[knives]

In our recent projects, we have proposed to entirely strike out preparation of piping orthos (or piping general arrangement drawings) especially if the project and client are looking for opportunity to reduce the cost. As you mentioned, if the 3D model (with iso drawings) are handed over to erectors, all the necessary details required can be taken from it. In the near future, I can only imagine that 3D model of the plant itself can be locally downloaded and viewed with same functionality as high end 3D model viewers (SPR and Naviswork) in a platforms like tablet and smartphones.

[knives]

Supports

It is recommended to provide adjustable type supports in suction and discharge piping for pump alignment purpose.

Y-type strainers

In order to improve access for cleaning, Y-type strainers for horizontal suction pipe should be installed pointing downwards or at an angle of maximum 45 deg (check bolt holes quantity) from vertical. Install Y-type strainer away from the pump if located on vertical suction pipe.

[knives]

A line requires PWHT and instead of welding a shoe directly at fabshop, a pad was provided instead then heat treated. Is it still required to perfom PWHT for the weld made at site if a weld between a pad and shoe was made?

[knives]

Thanks Mr. Jop for the suggestion. However, would that extra section of pipe extended to the supporting point be considered a dead leg?

[knives]

I think the original topic is not meant to address status of piping design jobs in US alone but on a global perspective.

So what if the detail engineering jobs are outsourced in India, China, Philippines or other Asian country. It could only mean that the career itself is growing globally.

[knives]

You haven’t specified what type of work and project stage you’re at but I would assume that you’re suppose to write it as part of the instruction to Contractor on next project phase.

That kind of work is kinda typical activity when you are in pre-FEED to FEED or FEED to EPC stage. You would have to narrate the philosophy of equipment layout, the level of detail of your input data and outstanding issues that the Contractor need to address on next phase.

Typically, the plant layout designer in charge of plot plan development would know these details and would write it as part of Project Specification.

[knives]

What would you design that would require a “longer” dead end platform?

In some energy company specification, there is also a minimum platform area (say 20 sq.m) where you need to drop a ladder as secondary means of escape. I think you can slightly veer away from the max. 20 ft requirement depending on where the platform location is. If this was on obvious hazardous area or there’s a high risk of fire from hydrocarbon handled by unit for example, I don’t recommend deviating on the specified dead end length.

[knives]

Never tried such arrangement before but have seen several on existing plant built by one respected EPC contractor during the 90s (not sure though if this is still in their current practice). In my opinion, such can be applied for olet on ordinary process drains. However, if the purpose of providing the olet is for some pressure or temperature instrument which might need an stable flow for proper read-out, then I think you should avoid placing olet on tee.

[knives]

Never tried such arrangement before but have seen several on existing plant built by one respected EPC contractor during the 90s (not sure though if this is still in their current practice). In my opinion, such can be applied for olet on ordinary process drains. However, if the purpose of providing the olet is for some pressure or temperature instrument which might need an stable flow for proper read-out, then I think you should avoid placing olet on tee.

[knives]

Preferred is upwind. But it can alternately be located on the sidewind. At some instance where it cannot be really avoided, the stack may also be located downwind provided that a gas dispersion study and consequence modeling was carried out for all potential release scenarios, and the required separation distance between release source and stack as per study was met.

[knives]

Preferred is upwind. But it can alternately be located on the sidewind. At some instance where it cannot be really avoided, the stack may also be located downwind provided that a gas dispersion study and consequence modeling was carried out for all potential release scenarios, and the required separation distance between release source and stack as per study was met.

[Author]

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