By Trevor Busch
Identified as a problem area for fire flows in the town’s Potable Water Distribution Master Plan delivered to council in June, the industrial area has been slated for future improvements to improve flow rates in the area.
“There are certain places that are going to have to be addressed moving forward for the future,” said Taber fire chief Steve Munshaw. “Studies in the past — Fire Underwriter’s Survey studies — have all indicated those are areas where we have to put some attention. But over the future, it’s underground infrastructure. They have to be tackled one job at a time and move forward slowly. I believe they’re working on that, and I’ve seen some movement forward.”
According to MPE Engineering’s report, the town’s existing water distribution system is satisfactory for the current needs of the municipality, but fire flows are considered to be low in various locations throughout the town, mainly in the industrial area where large fire flows are required.
Recommendations included upgrading pipe diametres and looping water mains in these areas, in order to increase fire flow sufficiently to meet requirements.
“Alberta Environment requires towns to provide a certain pressure, and the town meets that,” said Matt Harker with MPE Engineering during council’s June 13 regular meeting. “There’s no problems throughout the whole town with pressure requirements. But the fire flow demands are not mandated by Alberta Environment. They recommend that you follow the Fire Underwriter’s Survey document, which suggests residential areas should have approximately 4,000 litres per minute.”
To improve flow during fire flow conditions, dead end pipes can be extended to adjacent lines to form loops. Improved reliability will result from water having alternative routes to reach a service location if a particular pipe is out of service.
“The industrial area needs some major upgrades, only for flow, because there’s a big difference in required flow between an industrial area and a residential area,” continued Harker on June 13. “A residential area needs 4,000 litres per minute, and an industrial area needs 15,000 litres per minute. Currently, there’s six inch mains going through there which just don’t have the capacity to provide that level of flow.”
Under the master plan, recommended water distribution system upgrades total $4,450,000, and consist of the Heritage Water Loop ($280,000), 46th Avenue Water Loop ($740,000), 51st Street Cul-de-Sac Water Loop ($130,000), 50th Avenue Industrial Loop ($340,000), 62nd Street Industrial Upgrade ($2,120,000), Highway 36 Service Road Upgrade ($460,000), Lantic Sugar Service Road Upgrade ($220,000), and industrial area hydrants ($160,000).
The recommended upgrades, including all cast iron replacements, are estimated at $8 million, while water mains required for future growth (including the Eureka subdivision) are estimated at $7.5 million.
Actions recommended by MPE in the report included installing additional water mains to complete loops in the system to improve performance during fire flow conditions; upgrade undersized water mains to improve flow; and incorporate upgrades into the town’s infrastructure improvement plan to be completed in conjunction with other infrastructure works that the town proposes (roadwork, sanitary and storm sewer, overland projects) to ensure an efficient use of funds.
“If you think about looping a system, if you took a garden hose, and you just ran it straight out from your one tap, well that garden hose is the same three-quarter inch length all the way across, but you start branching, say, quarter inch lines off of that thing, it’s only going to have so much flow and then it’s going to be done,” said Munshaw. “But if you were to loop a hydrant so that garden hose comes back and loops back into a water support system — into another valve with pressure — it’s actually like doubling the three-quarter inch line. It’s like bringing it up to an inch and half line. Then you would have way more quarter inch lines that could be used off that at any given time. What it does is continues the flow, allowing the cycle to go right around in a complete circle. Any time you have a straight dead-end branch, you’re never going to have the same flows. Even if you can just take that ‘t’ over to another line, the flows almost double in size.”
To prevent issues from arising in the area under the current system during a potential fire event, Munshaw indicated varying approaches sometimes need to be implemented.
“There has been fires in the industrial area with hydrants with maybe lower volume. So as a tactic you have to bring your fire trucks in from multiple locations using different fire grid system. So a hydrant that is one line, you don’t want to try pulling multiple fire trucks off that same line. You want to go to another line or branch of it, so that you can feed off of different directions.”
Seventeen new hydrants have also been proposed in the industrial area to bring hydrant distribution closer to what is recommended in the Fire Underwriter’s Survey.
“You always have to make sure you have one every 150 metres for industrial, or one every 300 metres for residential. That’s a requirement for fire hydrants,” said Munshaw.