Planning involves more than modeling piping systems and sizing pipe. This presentation discusses the many other items that should be considered when doing system planning. Not all of the items discussed apply to every planning problem. However, these considerations will apply at some time to many various planning problems (new business load, system expansion, main replacement, governmental agency relocation projects). In conclusion, the paper stresses making sure that short term problem solutions fit a long term vision.
Over the past 50 years great strides have been made in pipeline and system modeling. I remember taking weeks to draw a schematic of the piping system, numbering elements and nodes, generating computer cards for each element and customer, assembling card decks, loading card decks into the computer, waiting all night for the computer to run and then plotting the results on a schematic by hand only to find out I made a mistake. Now we develop models directly from GIS systems, customers are assigned automatically based on their address, the computer runs the model in a matter of seconds and we have results plotted automatically on the computer. We make changes to the model and again get the results almost intananously. Being able to model systems has become a great planning tool. However planning involves more than modeling and pipe sizing and there are a number of other items a planner should consider. There are a number of factors associated with the following that should be considered:
Loads
Pressures
Supply
Route selection
Physical Barriers
System characteristics
Reliability
Past problems
Resources
Economics
Public & regulatory
Senior Management plans
Lead Times
This paper will elaborate the considerations regarding each of the above.
Determing the load to enter in a model is often one of the most difficult tasks. There are a number of factors to consider regarding loading. What's the peak hour rate, when during the day does it occur? Is it seasonal? Is any portion interruptible or is it all firm? Is any portion of the additional peak hour load coincidental with the existing peak hour? How was the peak hour developed? Is this going to displace any other existing load? Was it based on a daily amount? Was it from equipment badge ratings? How likely will all this equipment be on at the same time? Is any of the equipment stand-by? How the area is zoned or is it likely to change? Is there a local planning board to contact? What is the source of the iload information? Was it provided by a marketing representative or developer that has a good track record? Is it based on actual usage or load in similar area? Is growth occurring in this area or is it declining?
The following identify some of the factors which should be considered regarding pressure.
The Maximum Allowable Operating Presure (MAOP) often determines the highest pressure which may be used when designing a piping system.
