Juno, Markus, and Neptune. If cold weather and snow is a part of your winter experience, you’ll recognize those as the names of winter storms that have made the 2014-2015 winter season one of the worst on record so far for many regions. Boston, Massachusetts, in particular, has gotten the brunt of each storm, resulting in the obliteration of their 30-day snowfall record of 58.8 inches by more than 31 inches. Their total snowfall for the season stands at just under 8 feet, a number that’s sure to increase with yet another storm brewing every week. What makes Boston’s weather woes particularly dangerous isn’t just the low temperatures and poor road conditions. For homes and businesses, a greater threat lies in the weight of the snow piled on the roof. With steady snowfall over a short period and temperatures consistently too low to facilitate melting, the potential for a roof collapse is very real. The weight of snow is measured by determining the weight of the water content.

In meteorology, a common rule of thumb for determining the Snow Water Equivalent (SWE) is the 10-to-1 ratio. That is, 10 inches of snow typically melts down to 1 inch of water, and it’s the weight of the water equivalent that determines the weight of the snow. According to the National Oceanic and Atmospheric Administration, 1 inch of water weighs 5.2 pounds per square foot (psf), so 12 inches of powdery snow will weigh just under 7 psf. Wetter, more compact snow with a higher water content can weigh as much as 20 psf. Other points to consider are how long the snow has been there, whether any drifting occurred, or if there was any recent rainfall. Over time, snow compacts, which increases the weight, while the lower layer may have melted and refroze, becoming a layer of ice beneath the most recent snow. An inch of ice weighs just under 5 psf. Building regulations will differ depending on your location, with regions prone to high snowfall amounts requiring stronger roofs, but a typical roof can hold between 30 and 40 psf of snow.

Sloped roofs are designed to allow water runoff and shed snow. Buildings with flat roofs are more at risk, both from standing snow and the pooling that occurs once the snow starts to melt, which can lead to significant water damage. Additionally, roof structures such as dormers and chimneys or HVAC equipment can lead to snowdrifts building against these structures that exceed the allowable snow psf.how long does it take to thaw out an ac unit According to the Federal Emergency Management Agency, signs that your roof’s integrity has been compromised due to snow or ice load include:portable ac unit uk Contact your city’s buildings department to determine the required snow load capacity for your location and have a snow rake stored in your garage if the predicted snowfall totals exceed that amount. wood covers for air conditioning units

You can average how heavy or wet the snow is when shoveling to give you an idea of whether raking is needed. Aluminum Wall Vent - Reversible Backdraft Damper Galvanized Wall Vent - Reversible Backdraft Damper Motorized HVAC Damper – Normally Closed Motorized HVAC Damper – Normally Open Pressure Relief / Barometric Damper Dampers are essential to the HVAC system. HVAC dampers can monitor air flow, temperature and humidity throughout homes and buildings. Some dampers are adjustable metal plates installed inside of a duct to close off or control the volume of heating and air conditioning in a specified room or area. These dampers can be motorized or manual. In today’s world, energy costs are increasing rapidly. Dampers help home and building HVAC systems control the amount of conditioned air used in certain areas or rooms. Dampers can either shut off or allow air flow as desired and help to maintain comfortable temperatures for people and business equipment.

Multi- level homes and businesses benefit by having dampers in the HVAC system to provide more comfortable living or working areas. Zone and bypass controllers control the dampers by managing air movement through the air ducts. A zone controller controls the temperature and ventilation specifications in one or more zones or space by operating one or more zone dampers. A pressure relief or barometric damper ensures the air pressure caused by the zone dampers will not harm the heating and cooling equipment. FAMCO manufactures motorized, pressure relief and backdraft dampers. The FAMCO motorized HVAC dampers are available in spring return, multi blade and power open power close models. The ADO and ADC motorized dampers have a 24 volt or 120 volt motor option. End switches are also available with these models.  End switches allow another appliance to be operated when the damper has reached its full power position (either open or closed). The floating motor mount design assures proper alignment of motor, shaft and damper to prevent binding, while the clutch/coupler reduces the number of moving parts for greater service life.

All ADC and ADO units without the end switch come with a flow control adjustment so that the damper blade can be blocked from opening or closing 100%. Please keep in mind that the end switch will not work if the flow control adjustment is preventing the damper from reaching its full powered position. Our Multi-Blade Dampers are used for zone control, air inlet and exhaust applications. This damper is built with aluminum opposed blades and provides minimum weight with maximum strength. This features a high torque 24 or 120 volt motor, with power open and spring close blades. The parallel blade design provides smooth operation and efficient low leak sealing. The Power Open Power Close Dampers come with a high torque 24 volt motor that operates in both directions. This damper features an easy wire terminal and 3 wires to integrate with two or three zone systems and a rotation switch to set at “normally open” or “normally closed”. The FAMCO Pressure Relief Damper (often called a Barometric Damper) is commonly used to relieve built up pressure in zoned duct system that could potentially cause damage to HVAC equipment.