Double mechanical seal for hydrocarbon pumps

[terrorist]

We have single mechanical seals with API seal plan 11 installed with the OH1 pumps in pentane and naptha service. We are planning to replace these seals with dual mechanical seals so that HC does not leak in the atmosphere immediately in event of seal failure.
Is there any guidelines or standard (API/ OISD) which makes it mandatory for HC pumps (API 610) to have dual mechanical seals. I tried to find the same in API 682 but could not get any such guidelines.

 

[mk3223]

IMO, there is no requirement of the Code regarding the pump seal application. Instead, the selection of the pump seal type and application is the Owner's requirement for the reliability and environmental concerns, such as process leak caused by the seal failure or excessive emission due to the improper seal type.

 

[drc3]

IIRC, it may depend where you are in the world, and be driven by regulatory requirements - if you are subject to tight fugitive emissions standards then you may need a double seal to achieve acceptable containment of the normal sealing flow across the primary face. (But I may be victim of mechanical seal salesmanship here, fugitive emissions are not an area of great expertise).

 

[shashankTurbomachine]

There is no such guideline but as a prevention most HC is supplied with double mechanical seal.

Now, it depends whether Arrangement 2 or 3 is required.

if H2s is present more than 50ppm ,plan 53 is required.Also NACE is applicable.



A well phrased question has answers in itself!!!

 

[gyaneshwarp]

OISD 125 Clause 4.4.1C recommends Double Seal for C4 and higher hydrocarbon.
I will recommend double Face to Face seal with Plan 53 C