Separation distance between process units in Petroleum Refinery. Mitigation measures! 1

[piper1982]

We are working on a Hydrocracker project located in India. The code to be followed is OISD (Oil industry safety directorate).
As per the code separation distance between adjacent process units needs to be 36 meter considering 6 meter wide road between the units. The distance of process unit must not be less than 15 meter from the edge of the road.
In this particular case the adjacent unit is just 6 meter from the edge of the road. In order to satisfy the 36 meter clear gap with adjacent unit we are forced to have the hydrocracker battery limit 24 meter from the edge of the road.

The heater which is located in the south portion of unit is very close to the Piperack and doesn't satisfy the 6m clearance required between Piperack and Heater.

Are there any mitigation measures which can be applied which can help us in raising a waiver request to client/PMC to reduce the separation distance from 36 meter to about 34 meter. In LNG industry we use water curtains if we are not able to satisfy the minimum safety distance between the leakage point from High pressure source, but unaware about any such mitigation measures for refineries.

Also attaching snapshot from overall plot plan which shows the adjacent units and the snap from unit plot plan of Hydrocracker.

 

[LittleInch]

That's why I don't like prescriptive distances like this which whilst probably based on something from a long time ago, just get used without a proper review of the risks.

To be honest I would just ask for a deviation based on inability to locate within the site constraints.

If refused try a specific safety assessment.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Thats a can of worms. Kick the can down the road. Raise the violation to the client for their resolution. Add a change order for studying the situation, should they ask you to resolve the issue.

 

[piper1982]

Thank you for valuable insights. The concern was raised to client during preliminary discussions on plot plan.

The client/PMC are simply washing their hands off the issue and requesting the detail engineering contractor to resolve the issue. Ironically the FEED was done by the same company who is assigned as PMC on the detail engineering job. They should have identified this mess in the Feed stage.

The Piperack width has been already reduced from 10 meter to 6 meter where the heater is located. But the 15 meter radius of heater is affecting other equipment's which are on the north side of the Piperack. As pointed out by Little inch a safety assessment might be the right approach to drive our point to the client.

Some valuable insights by distinguished members from their past experience might help us to move in the right direction in resolving this issue.

Thanks

 

[LittleInch]

Tell you need more land then....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

First evaluate if the OISD has any provisions to allow something other than following their prescribed clearances? Are they recommended clearances, or are they required clearances? Mitigations of another kind may not be acceptable.

 

[GD2]

Piper1982,
To understand your point, below is the situation:
1. You work for an EPC entrusted to do Detail engineering.
2. The FEED was done by the current PMC.
3. FEED was approved by the Owner but don’t meet the OISD guidelines.
My questions are:
4. Is OISD guidelines incorporated by the local authority/regulator?
5. Do you have to do a design registration with the local/ state regulator?
6. How much mechanical work had been done during FEED in terms of construction excluding civil and structural?
7. What’s the cost impact if you need to comply with the rules of OISD?
My point is:
8. You were not responsible for the FEED design. You inherited all FEED design from the Owner.

Responsibly for wrong design falls with the designer. I am not sure about the rule in India that allows Owner to claim compensation for wrong design from the FEED contractor. If the claim period is over, they have to pay for the overrun or deal with the contractor.

If you are looking for mitigation measures, look through the OISD rules. If you are thinking about raising a waiver, they might throw it out of the window.

My final thought is: if you(your company) is responsible for design registration with OISD/local regulator, you better design in the right way.

In many countries, design drawings and documents had to be signed and stamped by an registered Engineer. The design engineer/ company is responsible for wrong design and Owner can sue the company if the equipment/plant was wrongly designed.

I don’t know about India.

GDD
Canada

 

[piper1982]

GD2,

Allow me to answer your questions.
Point 4:- Yes OISD Guidelines are mandatory. Its required for all oil and gad projects in India.
Point 5:- The plot plan has to be approved by the petroleum authority of India (PESO -

https://peso.gov.in/web/home)or

else it wont be insured and certificate of approval wont be issued.
Point 6:- No mechanical work(construction) has been done yet. Its in scope of EPC contractor.
Point 7:- Cost impact will be nominal. But the point is we don't have the plot space to incorporate the changes.
Point 8:- Correct.

Agree with your final thoughts. We have to design it the right way to avoid legal complexities later when the plant is in advanced stage. Hence the concern.

The detailing plot plan has to be approved by PESO. Or else the company will be slapped with a hefty penalty, Insurance premium will go through the roof to get the plant insured which is not OISD compliant.

Thank you

 

[LittleInch]

It's difficult from here to know what the interplay is between you, owner and PMC, but sounds like the PMC / FEED designer didn't lay out the plant in full compliance with the prescriptive OISD codes.

So there are a few options.

1) Read the code carefully and see what, if any, deviations are permitted or have historically been permitted by PESO. If any, see what the impact is (more barriers, increased thickness, gas detection etc etc)
2) If none then you need to spell out the issue in diagrams and plans to the client in a formal meeting and show that you can't comply with the requirements and that PESO don't accept deviations. Just keep to facts and drawings and try and prevent the PMC shouting you down.
3) Get a good lawyer to look through your contract and start preparing contractual letters as this probably won't end well.
4) Demolish or propose to relocate the heater or the other item which is causing a particular issue (and tell the client how much that's going to cost)
5) Look at ALL possible options and present them to the client, regardless of cost or practicality (see item 4).

Good luck and please tell us how you got on, if you're still working ont he project by then...

Oh and 6) Write EVERYTHING down and save all messages, reports, plans on a separate hard drive. You never know when they could get personal about something like this.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Look on the bright side. You might be able to retire on that one.

 

[GD2]

Piper1982,
You are saying you don't have extra plot/land. Why is that? Are you in an island?

GDD
Canada