Discharge header Vs Manifold

[mayor610]

Dear All,
We at a Municipal Corporation floated a tender for "replacement of Vertical turbine Pumps ( 2 w + 2 s) along with replacement of Column pipes and discharge header valves etc."for the raw water intake well.
Now the contractor while carrying out installation of Pumps claims that your contract does not include provision of " MANIFOLD" therefore he will provide only the discharge pipes. For "MANIFOLD"he deserves extra payment. The question is whether DISCHARGE HEADER is same as MANIFOLD or not? Please guide.

 

[mk3223]

Besides the title of the work scope, you may review your "Engineering Work Spec (or Order)" with the detail work scope with the Contractor. Hope that the "discharge header" or "manifold" was defined clearly with a detail sketch for the work. It's difficult to argue in both sides if the work detail was not well defined.

 

[LittleInch]

I would say they are the same thing.

However your quote above days "discharge header valves" which isn't the same thing.

It's difficult to believe they were no drawings clearly showing the demarcation between new and existing.

If not them make sure you do it next time to avoid any confusion.

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

 

[cvg]

a manifold is "a pipe or chamber branching into several openings" and a header is often synonomous. however, you may have both suction and discharge manifolds with the pumps, columns (barrels) and discharge pipes in between. based on what you have shown so far, it was poorly worded and the contractor has protected himself by excluding it. a pre-bid or pre-construction meeting to go over the scope and risks could have cleared all this up early on

 

[saikee119]

I have not come across vertical turbine pumps in raw waster intake well but the description sounds like vertical spindle wet well pumping system used in nearly all power plants.

I would say the owner of the works has a need to either specify the existing discharge manifold or header to be re-used or a total replacement of the same. Generally the description would be to enable the system to operate normally and to carry out the routine maintenance.

One can call a header or manifold but I think the real question is what is in it. Normally one would have flanges, reducers, isolation valves (sometimes doubled as for throttling too) and controlling devices to enable individual pump to be switched on, switched off, isolated, removed for servicing or replacement. It is rarely if ever one header directly bolted to every the vertical pipe of the wet well pump so that the entire system must be shut down if any single component needs repair/replacement. This arrangement clearly cannot work with a system with standby pumps.

Therefore I think if no instruction has been given to the bidder he can either bolt each vertical pump to the naked header or manifold or he provides isolation valve as minimum for each pump for which he has the right to seek reimbursement if no such detail has been specified in the contract. Without isolation valves the owner can't even select which pump to be a standby or operational.

I would expect a system with four pumps, two of which to be used as standby, to have flow meters, diverter valves, isolation valves, throttling/controlling devices, reducers, etc... in the system. If these have been described as the header system then the owner can insist on a header and reject any manifold not conforming with the specification.

I would be extremely surprise if a claim using the word "manifold" would stick at all.

 

[gerhardl]

This is, as very often, a purely juridical problem.

If the contractor has bid to your written description it would be very reasonable to understand this as a total replacement of an existing system. Especially if drawings sent with bid papers or at inspection on site shows this as a complete system.

In my mind any exclusions, even if it is a fairly open contract, should be described by the bidder.

I believe it is as simple as this, instead of discussing at length the content of technical terms.

 

[bimr]

Provide the actual text of the specification and the drawings and then someone may make an informed opinion.