Hot Tapping Near Pump Suction

[refiner258]

Is it acceptable to perform hot tapping near pump suction? API 2201 says to avoid hot tapping upstream of rotating equipment or automatic control valves, unless such equipment is protected from the cuttings by filters or traps .

Will pump suction strainer be sufficient for this?

 

[LittleInch]

Depends on the level of filtration in the upstream filter.

You're probably looking at something like min 80 mesh and possibly 120 or 160 for the duration of the cutting.

Pretty unusual to do it for plant piping in my experience.

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

 

[Aub_Engineer]

I have designed and implemented hot tap connections a few feet from the suction of a pump. Is there a spare pump that can run while the hot-tap is performed?

Our main concern was if the "coupon" that is cut out is unable to be retrieved. Some other items you should verify:
- Will the flow inside the pipe affect the weld quality of your hot-tap welds? Too much heat removal can decrease your chance of a successful hot-tap. You should research the Battelle Institute and some of their findings. Depending on your situation the flow may help or hurt you.
- The filter mesh should be sized based on the allowable particle size for the centrifugal pump. You should verify this is the case and then you will be ok from a pump reliability standpoint.
- Are there processes or equipment further downstream that could be affected?

 

[bimr]

When a hot tap is installed upstream of rotating equipment or control valves, strainers or other devices must be in place to prevent damage from metal shavings.

A hot tap shall not be considered a routine procedure, but shall be used only when there is no practical alternative. It is preferred to install nozzles during a turnaround, but installing a nozzle with equipment in operation may sometimes be advantageous, especially if it averts a shut down.

For each hot tap, ensure that the pipe has sufficient wall thickness, which can be measured with ultrasonic thickness gauges. The existing pipe wall thickness (actual) needs to be at least equal to the required thickness for pressure plus a reasonable thickness allowance for welding. If the actual thickness is barely more than that required for pressure, then loss of containment at the weld pool is a risk.

Hot Taps should only be installed by trained and experienced crews. Welding on in-service pipelines requires weld procedure development and qualification, as well as a trained workforce to ensure integrity of welds when pipelines are operating at full pressure and under full flow conditions.

 

[mk3223]

May consider the operation risk and business consequence of the potential pump damage as a result of the piping hot tap so close to the pump suction. Need to comply with the Company MOC requirement and involve the right peoples to review the proposal.

 

[georgeverghese]

Check with your plant process safety / technical safety engineer and your plant manager - the hazardous area classification around this pump will be key. In my opinion, you'll also need remote operable shutdown valves just upstream / downstream of this pump just in case things go wrong during the hot tapping.

 

[refiner258]

Thank you very much for everyone's valuable inputs. We will pursue hot tapping at the pump suction with the start up strainer in place. I will let you know how the hot tapping activity went once completed. Again, thank you very much.