Elimination of CMLs - Clean Non-Corrosive Hydrocarbon Service

[arcpro]

We have our clean service hydrocarbon piping systems where corrosion has not been found historically over a documented period of more than 10 years.
Within these similar services at our facility and the others, there has not been any incident of leak reported.
CMLs have remained active in these many years considering the facility has been newly commissioned and to be sure about the material of construction and other practices followed during fabrication.
Chances are considerable reduction of inspection effort and the cost associated in obtaining, recording, analyzing, and reporting all this inspection.
Suggestions please, if we consider elimination of CMLs on these non-corrosion clean hydrocarbon service piping systems.

[octane]

Very practical to do however without involving Corrosion Specialist, this may not be advisable to eliminate.
Other condition as I understand is the consequence if leak occurs. In hydrocarbon services, the corrosion issue if addressed may still be having higher consequence in case of a leak. Reduction to representative values will be good to go.

[mechcolor]

Go one by one and carefully apply in your case, as straight from API 570:
(1): 5.6.2: CMLs may be eliminated, or the number reduced under certain circumstances when the expected damage mechanism will not result in a wall loss or other forms of deterioration, such as olefin plant cold side piping, anhydrous ammonia piping, clean noncorrosive hydrocarbon product, or high-alloy piping for product purity. In circumstances where CMLs will be substantially reduced or eliminated, a corrosion specialist should be consulted.

(2): 5.6.2: CMLs can be eliminated for piping systems with any of the following characteristics:
a) extremely low potential for creating a safety or environmental emergency in the event of a leak;
b) noncorrosive systems, as demonstrated by history or similar service;
c) systems not subject to changes that could cause corrosion as demonstrated by history and/or periodic reviews.

(3): 5.6.2: Corrosion specialists should be consulted about the appropriate placement and number of CMLs for piping systems susceptible to localized corrosion or cracking, or in circumstances where CMLs will be substantially reduced or eliminated.

My understanding here is your mentioned clean non-corrosiove hydrocarbon service stands qualified for elimination following (1) as above.
2nd, I fear that you will consider (2)a hestitating to eliminate however code uses ANY of (2) all three cases and (2)b clearly applies here. Even (2)c would also. So still good to go for elimination.
3rd, corrosion specialist, if not you, would agree based upon the data ensuring no chances of any localized corrosion as well.

Make this an improvement project highlighting potential savings and you are all good to eliminate CMLs here.

[novice123]

With 5.6.2 where you mentioned the case (2) allows elimination based upon any of the applied cases which can support application on other services as well, qualifying these conditions. However, on top of this, like you clearly highlighted involvement of corrosion specialist is recommended.

Go one by one and carefully apply in your case, as straight from API 570:
(1): 5.6.2: CMLs may be eliminated, or the number reduced under certain circumstances when the expected damage mechanism will not result in a wall loss or other forms of deterioration, such as olefin plant cold side piping, anhydrous ammonia piping, clean noncorrosive hydrocarbon product, or high-alloy piping for product purity. In circumstances where CMLs will be substantially reduced or eliminated, a corrosion specialist should be consulted.

(2): 5.6.2: CMLs can be eliminated for piping systems with any of the following characteristics:
a) extremely low potential for creating a safety or environmental emergency in the event of a leak;
b) noncorrosive systems, as demonstrated by history or similar service;
c) systems not subject to changes that could cause corrosion as demonstrated by history and/or periodic reviews.

(3): 5.6.2: Corrosion specialists should be consulted about the appropriate placement and number of CMLs for piping systems susceptible to localized corrosion or cracking, or in circumstances where CMLs will be substantially reduced or eliminated.

My understanding here is your mentioned clean non-corrosiove hydrocarbon service stands qualified for elimination following (1) as above.
2nd, I fear that you will consider (2)a hestitating to eliminate however code uses ANY of (2) all three cases and (2)b clearly applies here. Even (2)c would also. So still good to go for elimination.
3rd, corrosion specialist, if not you, would agree based upon the data ensuring no chances of any localized corrosion as well.

Make this an improvement project highlighting potential savings and you are all good to eliminate CMLs here.

[mechcolor]

Thing here is to to make sure you inspect the right areas and those ONLY.
Managing the risk and keep that at an acceptable level.
Once that is achieved, you are in control and during review cycles when RBI triggers, make sure you check into the data, changes, any reported failures, incidents.