Case Study: Backflow Enclosures Excel in Extreme Cold Weather

St. John’s, Newfoundland, Canada has some of the harshest winters in North America. St. John’s low temperatures average between -4 degrees F and 14 degrees F during the winter months. St. John’s has on average 167 days of below freezing temperatures every year. That compares to 124 freezing days per year in Buffalo, NY and 122 freezing days per year in Chicago, IL. St. John’s is cold and windy as well. The average wind speed in St. John’s is 15 MPH. Compare that to our windy city Chicago’s average wind speed of 7.4 MPH. When it comes to protecting backflow preventers from these harsh conditions, the engineers in St. John's turn to above ground enclosures.

A Harsh Climate

So, is the harsh St. John’s winter environment suitable for above ground enclosures? You bet! In fact, the cross connection control engineers at St. John’s specify above ground enclosures that meet the ASSE Standard 1060. There are a number of requirements for ASSE 1060 enclosures, including strength, security and drainage. The most important part of ASSE 1060 is the requirement for freeze protection. ASSE 1060 class 1 requires the heated enclosure to maintain at least a 40 degrees F temperature inside when the outside temperature is as low as -30 degrees F. The way backflow enclosures achieve class 1 status is by combining insulation and a powerful heater.

All the panels on one of our industrial enclosures have 1½” of polyisocyanurate insulation cut to the exact dimensions of the panel. This material is commonly used in the roofing industry and is superior to the sprayed-on insulation typically used by fiberglass enclosure manufacturers. The R-value for polyisocyanurate insulation is the highest for rigid-board insulation at an average of 6.5 per inch. By using such a high quality material, the enclosures more than meet ASSE 1060’s R-8 requirement for insulation. Since hot air rises, most of the heat will escape through the roof. For this reason all panel design Safe-T-Cover enclosures have 3" of rigid-board insulation in the roof. That's more than twice the insulation required for ASSE Standard 1060.

Most enclosure heaters in the industry are wall-mounted at a minimum of 12” off the slab. Remember that heated air rises, so the most efficient heating occurs when the heater is placed as low as possible. For maximum heat retention, look for a heater that bolts directly to the concrete slab and produces both convective heat to the air and conductive heat to the slab. Some heaters installed in this way can provide heat that penetrates as much as 16 inches down into the vertical riser pipes. Click the link to learn more about ASSE 1060 class 1 heaters.

Extreme freeze protection

Safe-T-Cover has sold standard enclosures and large, custom enclosures in Newfoundland, Canada every year for the past 5 years. We know firsthand that backflow enclosures withstand the extreme cold temperatures and high winds encountered on Newfoundland year after year. Not only do they protect the equipment inside from freezing, they also provide testers and workers a safe place to do their job. The winters are so severe the St. John’s Cross Connection Control engineers prefer that those working on the equipment housed inside the enclosures have enough room to work INSIDE the enclosure in many situations. The workers can’t be exposed to the harsh outside conditions in the winter. This means the manufacturer must design the enclosure extra-large to make sure they have room to work. They must consider size among a variety of design considerations when manufacturing backflow enclosures suitable for this climate. Jim Sweetapple is the principal at J. D. S. Sales LTD in St. John’s, Newfoundland. He knows firsthand how important it is to provide a safe environment for workers. He says, "Harsh climate conditions demand that enclosures offer the opportunity for service and maintenance of equipment and allow workers a safe work space from extreme wind and cold weather which is common in St. John’s all year round.”  

ASSE 1060 Enclosures are Success

Jim says the durable above ground enclosures from Safe-T-Cover handle the extreme weather in Newfoundland well. “The City of St. John’s cross connection control office demands that all backflow enclosures carry ASSE 1060 certification. Safe-T-Cover's availability of ASSE 1060 certified standard models and custom enclosures built to the ASSE 1060 standard have been a great success." You'll likely find ASSE Standard 1060 class 1 approved enclosures are a good fit for your harsh winters as well.

In the image to the right, Jim is standing outside a custom sized above ground Safe-T-Cover enclosure installed earlier this year.

If you think above ground enclosures are only suitable for locations below the Mason-Dixon line, think again.