3.8 Design data and calculations. Design data and calculations and design
records shall be submitted for approval of the design review agency for each pump
class, design and size. Submittal shall be not later than submittal of design
drawings for approval. It is intended that the design data and calculations
shall be in sufficient detail to describe the design, physical appearance and
internal assembly to permit release for manufacture References listing the
author, publication, volume or text for all assumptions made in the calculations
and for all formulae or methods of computation not readily identifiable shall be
The following curves shall be provided:
3.8.1 Design performance curves.
Head versus flow.
Hydraulic efficiency versus flow.
Net positive suction head required versus flow.
Brake hp versus flow. This curve shall demonstrate that the
motor is not overloaded under any condition of suction head,
discharge head or free delivery possible within the pump
A discussion of the following design features shall
3.8.2 Design features.
Number of stages and reasons for selection.
Method of shaft sealing.
Type of coupling including previous service experience.
Those areas in which system design conditions, as furnished by
the design review agency, adversely affect pump reliability
or result in abnormal design features.
Steps required for disassembly and reassembly (including
alinement) to perform routine maintenance.
For sea water pumps the galvanic, wear, and galling compatibility
of the materials used for parts in contact with the pumped fluid.
Any other design features which the manufacturer considers of
significant interest to describe the proposed unit.
Whether the specified rated capacity and range of capacity (see
6.2.1) will result in shipboard operation at capacities that
will cause pump internal recirculation (suction or discharge)
sufficient to degrade pump life, performance or reliability.
3.8.3 Use of materials other than as specified herein shall be justified.
It is not intended that materials which conform to and are used as specified
herein shall require justification.
3.8.4 Calculations shall be submitted to cover the following:
(a) Shafting analysis of pump and driver assembly including
calculation of critical speed. If calculations are done
by a computer, the method of analysis shall be described
and only the results shall be submitted with identification
of corresponding pump parameters used in the calculations.
The following shall form the basis of the critical speed