The following is a summary of Estimation of Equivalent Length for hydraulic design

1. Estimation of Equivalent Length

When the piping lay-out is not available, the equivalent length (Le) of the piping will be estimated based on the straight length (Ls) as follows:

-Process Area:    3.0 times Ls
-Common Area:    1.5 times Ls
-Offsite Area:    1.3 times Ls

Note that Ls is the sum of xyz coordinate length.
For large size or high pressure piping, it is recommended to estimate the number of elbows,tees and valves and evaluate the equivalent

length, assuming piping lay-out.

2. Pump suction line

When the piping lay-out is not available, the equivalent length of the pump suction line should be assumed as 50m minimum for process pumps and utility pumps.

3. Expansion loop

For a long and hot service such as steam line, expansion loops which will remarkably increase the equivalent length will be provided, and should be taken into consideration.

a. Equivalent Length

The resistance coefficients (K) for valves and fittings are summarized in Table  in terms of equivalent pipe.  The equivalent length may be applicable for laminar flow.

b.Equivalent Length of Valve and Fittings

The following is a summary of input data to be prepared before the hydraulic design

1. Operational Data

-Service for identification
-Fluid name for identification
-Flow rate(s) of liquid and/or vapor
-Temperature
-Pressure
-Physical Properties

a. Liquid service:    Density,viscosity,vapor pressure,critical pressure,spgr@15oC
b. Vapor service:    Density,viscosity,molecular weight,Cp/Cv,Z-factor
c. Two-phase flow:Densities and viscosities for both liquid and vapor, surface tension

2. Construction Data

-Line class
-Elevation at inlet and outlet of piping system
-Distance between source and destination, sum  of XYZ coordinate length
-Instruments, types and quantities
-Valves and fittings, types and quantities, if available
-Control valves
-Pumps, compressors, and blowers

3. Design Requirement

-Marginal head of the pump NPSH available, if any
-Overdesign %: specification of the design flow rate, if any
-Turndown %: specification of the minimum flow rate, if any

4. Output from the Design

-Final Line size
-Pressure Balance
-Equipment Elevation

WORK STEPS:

1. Pressure Balance
2. Prepare input data
3. Pipe inside diameter
4. Line sizing
5. Evaluate equivalent length
6. Evaluate pressure drop of piping components
7. Check pump suction line, when pump is provided
8. Determine pressure drop of control valve
9. Sample Hydraulic Calculation

What is Scope of Basic Engineering

1. Scope of work during the Basic Engineering stage is categorized into 2 cases by the nature of the contract as follows:

Case A: FEED (Front End Engineering Design) Project
Case B: EPC (Engineering Procurement Construction) Project

2. FEED Project

-To perform execution work of the “Basic Design Package” in accordance with the Design Basis provided by Client.
-Company’s scope of work may extend to the upstream activities, such as preparation of the Design Basis as an adviser of the Client, and to the downstream activities, such as basic design development work.

3. EPC Project

-To perform basic design development work on the basis of the “Basic Design Package” which will be supplied by the Client as a part of the ITB (Invitation to Bid) Package.
-The basic design development work is the initial task of an EPC project, and the products of this activity are the inputs for the detailed design work.