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Spec Check Issue 7: Inline Pumps

3 min read

In this edition of Spec Check, we cover In-line Centrifugal Pumps. Pump specifications are sometimes too generic. When it comes to In-Line pumps, it is worth having a separate clause that is more specific to the In-line design. This will ensure that the pump supplied is appropriate and those pitfalls often experienced with poorly installed In-Line pump are avoided. If you have a meaningful specification, it forces the contractor to do it right!

We have 4 helpful tips to aid you when specifying In-Line pumps. You will prove it helpful to review and compare your Master Template

  1. Ensure the In-Line pumps have the Back Pull Out capability
  2. Ensure the installation does not impede the Back Pull Out function.
  3. Ensure the motor fitted is not a cheap import that is non-compliant.
  4. Ensure the motor is not an extended shaft type but has a Muff Coupling arrangement.

We will explain each of the above separately and give you suggested clauses to include in your Master Spec.

Picture 1: Inline BPO Feature

 

  1. Ensure the In-Line pumps have the Back Pull Out capability: Suggested Clause: All in-Line pumps that are floor mounted will be single-stage centrifugal with vertical shaft perpendicular to the Inlet & Outlet of the pump. Casing to be Cast Iron construction with integral mounting plate for base mounting. Suction & Discharge ports to be flanged and opposite. Refer Picture 1.
  1. Ensure the installation does not impede the Back Pull Out function: All too often, there are obstructions above the pump, so repair work in the future becomes a nightmare for the owner, whereas it should be a very streamlined operation. Suggested Clause: Ensure when installing the Vertical In-Line pump, avoid pipework above the pump so there is clear access space maintained above the motor to allow positioning of an overhead Block & Tackle. Liaise with the Builder to have an Anchor Bolt installed in the concrete so it fits directly above the centre line of the motor.
  1. The motor fitted is not a cheap import that is non-compliant. There are numerous pump manufacturers across the globe that purpose build motors to suit their own pump. This poses a real problem for the client(end-user) when a replacement is required in the future. Far better to have a standard IEC motor fitted to ensure a replacement can be obtained from any of the metric frame motors manufactures such as Teco, Weg, Toshiba which are readily available locally. Check you electric motor master specification. If it refers to metric frame IEC motor MEPS compliant, then you will be covered. Suggested Clause: Electric motors shall be Totally Enclosed Fan Cooled (TEFC), MEPS compliant with Metric Frames as specified in this document under Motors & Drives.

 

Picture 2: Shows stub shaft arrangement.

 

  1. Ensure the motor is not an extended shaft type but has a Muff Coupling arrangement. This point ties in with Point 3 above. Picture 2 shows a pump shaft with a Muff Coupling on end. The motor end is bored to suit the metric frame motor and secured to the motor shaft. This allows the motor to be removed and replaced with locally supplied MEPS motor. The alternative to this is for the motor shaft to be extended so that it becomes the pump shaft also, thus making it a non-standard motor. This is to be avoided as it causes headaches and downtime down the track when a replacement motor is required. See Picture 3. Suggested Clause: In-Line pumps that have electric motors with extended shafts will be rejected. Pump Shaft must be separate to the motor shaft and connected by a Muff Coupling arrangement so that motor can be disconnected and replaced with Metric Frame motor readily available from local motor suppliers.

Picture 3: Extended shaft shown – Motor shaft becomes pump shaft.

 

 

Action Points:

  1. Check you Master Specification for Centrifugal Pumps. If you have a separate In-Line pump clause, then check for the above issue. Edit accordingly.
  2. If you don’t have a separate clause then maybe add one with the above clauses this could be added to your Pump Specification with a Sub Clause “ In-Line Centrifugal Pumps”.
  3. Note: Please note the above applies to floor mount BPO Inline NOT to pipe mounted circulators which should have their own clause.