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Piping Engineer Question
2

Piping Engineer Question

Piping Engineer Question

(OP)
Hi there!
In P&ID somewhere along showing Off-spec, This is process specific, i am not assigned in this project so inter disciplines questioning is impossible. Could you please explain to me "off-spec".

Regarding on P&ID matter, somewhere showing NNF, its put under along the line same as slope symbolized, Could please explain what does "NNF" mean?

Kindest regards

tranvietnga1905

RE: Piping Engineer Question

Off-spec means that the part in question does not meet the specification for that part.

Can't help with NNF - sorry.

RE: Piping Engineer Question

I've not seen NNF before, but I would suspect it to mean something like "Normally No Flow"

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

"All the world is a Spring"

All opinions expressed here are my own and not my company's.

RE: Piping Engineer Question

I have seen NNF on P&IDs before.  It was to indicate 'normally no flow' as StressGuy indicated.

RE: Piping Engineer Question

(OP)
Thanks a lot master-minded guys,

Regards


RE: Piping Engineer Question

Re off-spec,

Wouldn't it be a bit odd to either deliberately design something that contains an off-spec part = specify it as off-spec on the project P&ID, or, in case of an as-built P&ID, find out that a certain part is off-spec and, rather than replacing it immediately, mention that on the as-built P&ID?

Instead I would tend to think that off-spec indicates a piece of pipe that contains off-spec product, a rundown to slop or feed tankage.

RE: Piping Engineer Question

In our industry, clients have their standard guidelines and specifications that we are required to use on every project but occasionally they will agree to something that doesn't comply with the standard specs if it has been offered for good reason. In this situation, the part could be highlighted as "off-spec" so the clients operator is aware he is getting something that is different from usual.

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