Winter Storms & Cold Weather

Preparing for Winter Storms & Deep Freezing

However tempting it is to turn down the building's thermostat to conserve fuel during cold weather, don't.  The clean-up costs of burst water pipes from freezing are much higher than the cost of the fuel saved. Building and room thermostats should never be set lower than 55 degrees. Keep thermostats above 65 degrees when the weather may dip below 0 degrees or when the facility is to be unoccupied for a weekend or longer. Note: closed-in areas of your buildings that have poor air circulation are likely to be much colder than in the room itself, causing pipes located there to freeze.

Some cold weather safety precautions to prevent frozen pipes include:

• Installing low temperature alarms.

• Removing barriers to the flow of warm air; for example, removing some ceiling tiles to allow air circulation.

• Maintaining the heating system.

• Ensuring adequate fuel supply for heating system over weekends and school vacations.

• Draining unused water systems.

Also, consider using antifreeze solutions in non-potable water systems, or using UL or equivalent heat tape or similar products on pipes. But consult a professional first about how to apply and use heat tape, as improper use can cause a fire. Download the Preventing Frozen Pipes pdf.

Deep Freeze

During a "deep freeze," when temperatures drop below 20 degrees.

• Schedule regular building "Freeze Watches," during winter storms and cold weather.

• Turn thermostat to 65 degrees or higher.

• Open cabinet doors to allow warm air to circulate around plumbing pipes.

• Let water trickle from faucets that are served by exposed or vulnerable pipes. Even a small trickle of water flowing through the pipe will help prevent it from freezing.

Remember, temporary or portable heating devices should not be used by the building occupants for supplemental heating. These devices should only be used by facilities personnel for emergency purposes.

For additional information, download Preventing Frozen Pipes, Snow Loading,  Property Protection. See also Risk Transfer for Snow Removal, and HSB's Preventing Cold Weather Property Damage.

Removing Fallen Trees

Crews should use follow these precautions during tree clean-up: Tree Removal-Brush; Chain Saws; Chippers; Refueling Equipment.

Use of Emergency Generators

Standby generators make life easier during power outages, but if used improperly, they can be deadly. During an outage, electricity from your generator can backfeed the power lines, killing or seriously injuring line crews who are working to repair the lines.
A transfer switch stops backfeeding, and also makes using your generator much more convenient, allowing appliances to be operated much like when the power is on. Download guidelines for use of Generators  and Portable Generators.

Caution is imperative when working with or around electrical sources, especially during clean-up operations. Download HSB's Guidelines on use of Standby Generators, and these OSHA guidelines for on-the-job electrical safety.

Power Surges: Protecting Computer, Electrical Appliances, and
Electronic Equipment

During an outage, you should turn off and unplug electronic equipment to prevent damage when power is restored. The most common and often most expensive damage happens when the power comes back on and a surge of electricity floods the open circuits in the building. Power surges may also happen when other parts of the grid in close proximity are brought back up. Generally, a surge is a power increase that exceeds the peak voltage of 169 volts and lasts more than three nanoseconds a (power spike is shorter in duration). Surges can instantly overload and short the circuitry of computer and electronic equipment. A surge can cause computers to lose data, electronics to overheat, malfunction of  electronic equipment such as heating systems and alarm equipment. Sometimes a surge can cause fires. Surges can also cause cumulative damage, incrementally decreasing the lifespan of televisions, computers, appliances, and printers. 

Sensitive electronic equipment should always be plugged into UL listed surge suppressors that protect electric circuits. Surge suppressors are available from your local hardware and electronics stores. Look for surge suppressors with UL 1449 2nd edition and UL 497a listings. There are several types of protection against power line disturbances and outages:

Point-Of-Use Surge Protection Devices (SPDs). TSPDs combined with a good grounding system, should protect electronic and electrical appliances from most electrical surges. An SPD does not suppress or arrest a surge; it actually diverts the surge to the ground.

One familiar point-of-use surge suppressor looks like a regular plug strip. However, unless it specifically says so, don't assume a power strip provides surge protection.

• Make sure any surge protectors you purchase are listed as UL Standard 1449. This is a national benchmark and means the product has been thoroughly tested.

• Select a point-of-use surge protector that has an indicating light and/or audible alarm to show when it needs a replacement.

• Look for SPDs that come with a manufacturer's warranty. Some warranties cover only the device; others also cover any damaged equipment connected to the device.

• Direct lightning strikes are powerful enough to overwhelm even the best surge protection; that said, the ultimate surge protection is to unplug equipment from the wall if you suspect a surge might be coming.

Uninterrupted Power Supplies (UPS). There are a variety of power protection devices to protect data and equipment from damage caused by power outages or power quality problems. The most common systems are known as uninterrupted power supplies (UPS). There are three different types of UPS systems.
Off-Line. Off-line systems consist of a battery and a switch to sense power irregularities. The equipment is usually connected directly to the utility, and power protection is available only when voltage dips to the point of an outage. Some off-line UPS systems include surge suppression circuits, and some have optional built-in power line conditioners to increase the level of protection. For power sags, electrical line noise and brownouts, off-line UPS systems protect only when the battery is delivering power to the protected system. An off-line UPS protects only if the inverter is operating and on battery. Since off-line UPS equipment provides only partial protection against many common power problems, they are most often used to protect single-user PCs and other less critical applications.
   
Line-Interactive. These hybrid systems try to give better performance by adding voltage regulation features to off-line systems. They provide moderate protection against high-voltage spikes and switching transients. These systems offer adequate protection as long as the power sags are not continuous. At those times the system is being used frequently and may not be able to recharge for use in a power outage. Ferroresonant UPSs, another type of hybrid technology, keep the inverter in standby mode similar to other line-interactive systems, but they also maintain a reserve of energy that is usually sufficient to power most computers (i.e. PCs) briefly when a total outage occurs. Ferroresonant UPS systems work best with most non-computer technology or linear loads such as motors, beaters and lights.

On-Line. On-line UPS systems provide the highest level of protection for the most important equipment. These systems use a combined double-conversion (AC to DC/DC to AC) power circuit and an inverter, which continuously powers the load, to provide both conditioned power and outage protection. They provide protection and isolation from all types of power problems, including power surges, high-voltage spikes, switching transients, power sags, electrical line noise, frequency variation, brownouts and blackouts. These systems are often used for mission-critical applications that require high productivity and systems availability.