What are the minimum requirements in preparation of corrosion coupons?
If not installed initially, can they be considered to be installed? What should be the controlling /monitoring protocols?
Corrosion coupon preparation
Re: Corrosion coupon preparation
I would recommend you to follow NACE requirements as-is to apply any corrosion coupons.
And yes, you can install while in operation as well. In fact, many facilities introduce coupon monitoring later due to:
RBI recommendations
Unexpected corrosion findings
New damage mechanisms
Process changes
Chemical treatment optimization
Life extension programs
From an RBI perspective, installing coupons later is considered a risk-reduction and condition-monitoring improvement, not a deficiency.
However, there are considerations:
Historical corrosion trends will not be available.
Initial RBI calculations will continue to rely on inspection history and estimated corrosion rates until sufficient coupon data are collected.
Several exposure cycles (typically 2–4) are needed before trends become meaningful.
And yes, you can install while in operation as well. In fact, many facilities introduce coupon monitoring later due to:
RBI recommendations
Unexpected corrosion findings
New damage mechanisms
Process changes
Chemical treatment optimization
Life extension programs
From an RBI perspective, installing coupons later is considered a risk-reduction and condition-monitoring improvement, not a deficiency.
However, there are considerations:
Historical corrosion trends will not be available.
Initial RBI calculations will continue to rely on inspection history and estimated corrosion rates until sufficient coupon data are collected.
Several exposure cycles (typically 2–4) are needed before trends become meaningful.
Re: Corrosion coupon preparation
NACE Standard Practice SP0775 contains details on recording data, and interpretation of coupon data after you install & monitor.