Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Beyond an Average Day - How Much Water Should You Store?


Published on

  • Be the first to comment

  • Be the first to like this

Beyond an Average Day - How Much Water Should You Store?

  1. 1. Beyond an “Average Day” How Much Water Should Be Stored Dan Barr, PE Burgess & Niple, Inc.
  2. 2. Introduction <ul><li>A comprehensive, innovative, and straightforward storage and pumping analysis that will help determine: </li></ul><ul><ul><li>Distribution system capabilities during critical conditions </li></ul></ul><ul><ul><li>Current and future storage/pumping requirements </li></ul></ul><ul><ul><li>Determine and test proposed solutions </li></ul></ul><ul><ul><li>District by district requirements </li></ul></ul><ul><ul><li>Combines many storage concepts into one analysis. </li></ul></ul><ul><ul><li>Incorporates minimum turnover requirements </li></ul></ul><ul><ul><li>No mysterious factors or multipliers </li></ul></ul>
  3. 3. Analysis Components <ul><li>This analysis determines the minimum required storage volume for each of the following components: </li></ul><ul><ul><li>Operational (balancing and turnover) </li></ul></ul><ul><ul><li>Fire Protection </li></ul></ul><ul><ul><li>Outages </li></ul></ul>The Three Components of Storage
  4. 4. Analysis Data Requirements <ul><ul><li>Water demands by district is ideal </li></ul></ul><ul><ul><li>Existing system storage volumes </li></ul></ul><ul><ul><li>Existing pumping capacity </li></ul></ul>
  5. 5. Emergency Outages <ul><li>This component deals with situations when the source(s) for each district is out of service. </li></ul><ul><ul><li>Assumptions for determining minimum outage volume: </li></ul></ul><ul><ul><ul><li>The minimum number of hours the system must operate on storage alone </li></ul></ul></ul><ul><ul><ul><li>The demands during the outage </li></ul></ul></ul><ul><ul><li>The system’s emergency management plan must coordinate with these assumptions </li></ul></ul>
  6. 6. Emergency Outage Equations <ul><li>Minimum Storage Volume </li></ul><ul><ul><li>Demand (gpm) x Outage Requirement (hours) x 60 (minutes/hour) = Required Volume (gal) </li></ul></ul><ul><li>In Millions of Gallons Per Day </li></ul><ul><ul><li>Demand (mgd) x 1,000,000 gal/mil gal x Outage Requirement (hours) / 24 (days/hours) = Required Volume (gal) </li></ul></ul>
  7. 7. Fire Protection <ul><li>This component is sized by determining the design fire in each district. </li></ul><ul><ul><li>The design fire is an assumption based on a number of factors </li></ul></ul><ul><ul><ul><li>Local fire department requirements </li></ul></ul></ul><ul><ul><ul><li>Organizations like ISO, Inc. that publish public fire protection data </li></ul></ul></ul><ul><ul><ul><li>Ohio Fire Code </li></ul></ul></ul><ul><ul><li>Begin analysis after choosing design fire </li></ul></ul><ul><ul><ul><li>How much of required fire flow rate can be delivered by system pumping </li></ul></ul></ul><ul><ul><ul><li>What portion of the design fire will need to be delivered by system storage </li></ul></ul></ul>
  8. 8. Fire Protection Equations <ul><li>Capacity Available for Fire Protection </li></ul><ul><ul><li>Firm Pumping Capacity (gpm) – Maximum Day Demands (gpm) = Pumping Capacity available for fire protection (gpm) </li></ul></ul><ul><li>Required System Storage </li></ul><ul><ul><li>[Design Fire Flow Rate (gpm) – Available Pumping Capacity (gpm)] x [Design Fire Duration (hours)] x (60 minutes/hour) = Required System Storage (gal) </li></ul></ul>
  9. 9. Operational Storage <ul><li>This component includes storage volume utilized for: </li></ul><ul><ul><li>Daily turnover of the tank </li></ul></ul><ul><ul><ul><li>Tank turnover is used to keep stored water fresh </li></ul></ul></ul><ul><ul><ul><ul><li>Current industry practice and the Ohio EPA’s recommendation: </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Turnover 20% to 40% of the tank every day </li></ul></ul></ul></ul></ul><ul><ul><li>Maximum hour balancing </li></ul></ul><ul><ul><ul><li>Storage required to supply demands over the system’s pumping capacity </li></ul></ul></ul>
  10. 10. Operational Equations <ul><li>Turnover </li></ul><ul><li>Storage Volume (gal) x Turnover Target Percentage (%) = Required System Storage (gal) </li></ul><ul><li>Balancing </li></ul><ul><li>Maximum Hour Demand (gpm) – System Pumping Capacity (gpm)] x 8 hours x 60 (minutes/hour) = Required System Storage (gal) </li></ul>
  11. 11. Total Required Storage Volume Per District <ul><li>After calculating the three component volumes (emergency outage, fire protection and operational storage) determine the total required volume by: </li></ul><ul><ul><li>Adding all three components </li></ul></ul><ul><ul><li>Adding operational component to the larger of the two volumes for outage and fire protection </li></ul></ul><ul><ul><li>Sizing the required tankage on the largest of the three components </li></ul></ul><ul><li>Final parameter: </li></ul><ul><ul><li>Determine if the district has enough average daily demand to turn over the required storage </li></ul></ul>
  12. 12. Maximum Sustainable Storage <ul><li>(5)x(average daily demand) = Maximum Sustainable Storage for 20% turnover. </li></ul><ul><li>(4)x(average daily demand) = Maximum Sustainable Storage for 25% turnover. </li></ul>
  13. 13. Final Steps <ul><li>Determine remedies for deficiencies discovered during the process. </li></ul><ul><ul><li>Problems can be solved by a combination of: </li></ul></ul><ul><ul><ul><li>Increased pumping capacity </li></ul></ul></ul><ul><ul><ul><ul><li>May solve fire flow problem economically </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Power or mechanical failures could occur </li></ul></ul></ul></ul><ul><ul><li>Increased storage volume </li></ul></ul><ul><ul><ul><li>Increases emergency outage capacity without fear of mechanical or power-related failures </li></ul></ul></ul><ul><ul><ul><li>Expensive, might have siting issues </li></ul></ul></ul><ul><ul><li>Reduced demands </li></ul></ul><ul><ul><ul><li>Usually not possible unless customers can be shifted to another neighboring pressure district </li></ul></ul></ul>
  14. 14. Common Situations <ul><ul><li>Too much storage </li></ul></ul><ul><ul><li>Too little storage </li></ul></ul><ul><ul><li>Storage in the wrong place </li></ul></ul>
  15. 15. Questions? <ul><ul><li>Preformatted spreadsheet with calculations available </li></ul></ul><ul><ul><li>Contact: </li></ul></ul><ul><ul><li>Dan Barr, PE </li></ul></ul><ul><ul><li>[email_address] </li></ul></ul>