Don

Don't Let Your Liquid Assets Become Frozen

Working in sub-zero temperatures? Here is how to ensure reliable heated water for drench showers and eyewashes.

The realities of weather are always present on a job site and must be carefully considered by safety managers. Fortunately, today’s advanced water heating technologies make emergency drench showers and eyewashes fully operational 365 days per year, whether it’s or -40 degrees Fahrenheit sub-zero or 120 degrees Fahrenheit above zero.

Speaking of brutally cold weather, the coldest temperature in the U.S. was documented in Alaska when temperatures plunged to -80 degrees Fahrenheit below zero on Jan. 23, 1971 in Prospect Creek in central Alaska.1 The highest temperature in the U.S. and worldwide, 134 degrees Fahrenheit, was recorded in Death Valley, California, on July 10, 1913.

There are a variety of eyewashes, drench showers and water heating technologies that help keep employees safe in extreme, frigid environments—even if there is an absence of plumbed water. These freeze-protected products can be installed outdoors in places ranging from petrochemical facilities, offshore platforms, oil and gas refineries, power generation plants, mines and so on.

Safety Showers in Freezing Environments

Extreme environments can lead to many concerns when it comes to safety showers. Sub-zero temperatures can cause pipes to break or burst and cause systemic damage affecting the usability of the safety equipment. ANSI/ISEA Z358.1 Section 4.5.5 states, “Where the possibility of freezing conditions exists, the emergency shower shall be protected from freezing or freeze-protected equipment shall be installed.”

No matter the weather, the current ANSI/ISEA Z358.1–2014 American National Standard for Emergency Eyewash and Shower Equipment calls for emergency eyewashes and drench showers to deliver tepid water (60–100° F/15.5–37.7° C) for a full 15 minutes to ensure adequate flushing of hazardous materials from users' bodies and/or eyes. For drench showers the minimum flow rate is 20 GPM (76 L-MIN), for Eye/Face Wash the minimum flow rate is 3.0 GPM (11.4 L-MIN) and for Eye Wash the minimum flow rate is 0.4 GPM (1.5 L-MIN).

Moreover, for quick and easy access, it’s recommended that eyewash stations be within 10 seconds or 55 feet (17 meters) from a potential hazard. In some cases, it is necessary to supply heated water to more than one safety shower simultaneously. The water for all equipment must sustain the required temperature, volume and flow for the requisite amount of time needed. It is also important to inspect and test the eyewash and drench showers on a weekly basis. The ANSI/ISEA Z358.1 standard requires a weekly activation to ensure flushing fluid is available and to completely flush out stagnant water from the dead leg.

The bottom line is to ensure that all plumbed emergency safety equipment—despite any environmental conditions—has access to properly heated water to help avoid worker injury, prevent workers from having to use ice cold water (or discovering the pipes are frozen) in the event of an emergency, avoid equipment downtime and costly repairs and help encourage peace of mind for all employees.

Freeze-Protection Options for Emergency Showers

The following are adaptable safety shower products and engineered solutions that help meet ANSI/ISEA requirements in both freezing and challenging settings, including enclosed safety showers, heat trace units, frost-proof units, gravity fed units as well as electric tankless water heaters used to supply water to these units.

Enclosed Safety Showers. When harsh environments—extreme weather and highly corrosive conditions—can affect the performance of emergency safety fixtures, enclosed safety showers are necessary for providing a safe refuge. No matter what unique environmental conditions exist, these units can be custom engineered to any particular application with turnkey shower, eyewash and drench hose systems.

These freestanding units are insulated and heated to keep the internal temperature warm down to -40 degrees Fahrenheit (-32 degrees Celsius), making them ideal for sub-zero applications. They also include lighting and a signaling system to provide an audible/visual notification when the safety shower has been activated. The signaling system can also be tied into a remote monitoring facility for faster response.

While some units require a plumbed water supply, there are also self-contained units that will only require a full tank of water and a constant power source. Enclosed safety showers feature the ability to provide tepid water via a tepid water inlet, a hot water tank and a thermostatic mixing valve, a heated self-contained storage tank, or a tankless hot water heater. In accordance with ANSI/ISEA Z358.1 Section 7.4.4, safety systems such as enclosed safety showers with multiple drenching platforms (shower, eyewash and drench hose) must be capable of simultaneous activation while delivering tepid water for 15 minutes.

It is important for these units to be certified to ANSI Z358.1 and consider local electrical (CEC AND NEC) codes along with any explosive atmospheres that may be present. When necessary, these units can be built for Class 1 Division 1 or Class 1 Division 2 hazardous locations. In all, enclosed safety showers address the physical and psychological needs of the injured party by providing privacy, delivering unlimited tempered water, warm ambient temperature and a shelter from the elements.

Heat Trace Units. Heat trace units guard against frigid temperatures so that water does not freeze in the fixture, putting safety fixtures at risk for frozen pipes and parts. These specialized showers, available as combination shower and eyewash units, feature insulated jackets over an electrical heat trace cable that wrap the piping and protects the water from freezing. Should power fail in cold temperatures, these units feature a freeze protection valve that will open when the water temperature drops below 35 degrees Fahrenheit and bleed out water until it warms up again.

Some units are protected from freezing down to -50 degrees Fahrenheit (-46 degrees Celsius). Like enclosed safety showers, these showers can be built for Class 1 Division 1, Class 1 Division 2 and Class 2 Division 2 hazardous locations. An indicator light can be included to show when power is on and when the heat trace cable is heating the unit. In areas where high winds are prevalent, some units feature entire bowls and bowl covers to protect against wind, debris and weather. In especially harsh environments, stainless steel eyewash bowls with covers may be used for extra protection from the elements. These models come standard but are configurable as well.

Self-contained Safety Fixtures. When a work environment does not have plumbed water, self-contained, portable gravity fed eyewash units can be an excellent choice. These convenient systems incorporate water tanks that provide adequate water volume to complete a full 15-minute flush of the eyes at the ANSI-mandated flow rate. Some units are designed with hinged eyewash trays that may be activated in one quick motion, while stainless steel clamp mechanisms secure the tank during transport. When there is a risk of freezing temperatures, gravity fed units can be installed with freeze protection equipment, like a heater jacket. These units can be used with moveable carts to catch and drain fluids. For specialized situations, gravity fed emergency showers/eyewashes are available. These feature galvanized steel structures and large overhead gravity fed units. In cold environments these models can include an immersion heater to ensure tepid water as well as a heated enclosure to protect the user from freezing temperatures.

Electric Tankless Water Heaters. Tankless water heaters are an excellent option for providing heated water “as needed.” These portable units provide an unlimited amount of water heated at a specific temperature on demand, which makes these water heaters ideal for eyewash and drench shower systems. Unlike a thermostatic mixing valve that requires an ample supply of hot water, tankless water heaters only require access to a cold water supply and a source of power.

Additional benefits of tankless heating units are they draw energy only when needed, reach the ANSI standards for tepid water temperatures in 20 to 30 seconds, hold outlet temperature to within ± 1 degrees Fahrenheit, and have a low pressure drop (as low as 8 pounds per square inch). These features minimize potential post-installation complications that could be caused by a sudden decrease in pressure.

Newer water heaters are designed with redundant safety and anti-scald features to meet ANSI tepid water requirements. They also provide overshoot purge protection that will automatically open to purge excess hot water whenever necessary.

Optional features for tankless systems include NEMA stainless steel enclosures, explosion proof purge system, and freeze protection to -20 degrees Fahrenheit (-28 degree Celsius).

Custom Designed Solutions. For challenging applications that require more complex and flexible emergency shower or tepid water systems, systems can be configured based on unique specifications. Variables such as facility size and spatial configurations, plumbing requirements and special needs, and goals and budgets undoubtedly make each application distinctive and one-of-a kind.

In specialized cases, engineering specialists can design custom solutions incorporating key eyewash, drench showers and tepid water delivery systems. For example, this might involve the use of specialized tankless water heaters and portable skid systems (pre-piped, insulated, heated and assembled on steel skids) to supply water in difficult-to-access locations.

For selecting drench showers and eyewash equipment—especially when dealing with an extreme environment—consulting with manufacturers and safety specialists is highly recommended. These experts can identify the best equipment choices and specialized configurations for providing a safe and dependable ANSI-compliant work environment.

This article originally appeared in the February 1, 2022 issue of Occupational Health & Safety.

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