When people think of risks involved in Public Safety, usually the first responders come to mind, out in the field fighting crime and saving lives every single day. But those who work behind the scenes in Data Centers must also be aware of the dangers involved in working around and with such highly powerful equipment.
One such consideration deals with effective electrical safety. Because mission critical communications must be available round the clock, every day of the year, there will be times when energized equipment must be worked on, and personnel must know how to do so safely.
The two types of electrical accidents come from two different types of faults (commonly known as short circuits): electrical shock comes from a bolted fault which is solidly connected, and arc flash occurs when an arc fault causes the air to become ionized and conductive.
Electrical shock can cause extreme pain, respiratory arrest, and severe contractions at only .05 amps, but even currents as low as .006 can be dangerous if humans come in contact with it. Ventricular fibrillation will occur at 1-4.3 amps, and probable death and cardiac arrest are the result of 10 amps.
Arc flash is said to occur as often as 5-10 times per day in the United States alone. An arc flash event causes air to reach 35,000°. For the sake of perspective, the sun's average temperature is 10,000°. This air is also affected by a pressure wave of 300-500 lbs. per sq. inch, a sound wave of 160 dB (while the average jet engine is 120 dB), a fireball that moves at 5,000 ft per second and contains molten metal droplets and harmful copper vapor. This type of phenomena will cause serious injury and probably death if safety measures have not been taken. See video below.
OSHA regulation 1910.269 cites the National Fire Protection Association (NFPA) Standard 70E, which addresses safety-related work practices including working conditions, personal protective equipment (PPE), maintenance requirements, and proper labeling and authorization. Failure to apply these regulations can result in fines, law suits, or worse: injury and loss of human life.
These regulations require sensitive equipment to be properly tagged with boundary distances, and PPE requirements. This calls for an Arc Flash Hazard Analysis. Putting these practices into play can be costly to a center, but the risk involved with not having them is far greater. The unfortunate truth is that many Data Centers across the nation do not have arc flash or electrical safety programs implemented. If this is the case in your center, make it right today.
Even if your center outsources electrical work, anyone who works near electrical equipment should be educated, and someone should be appointed to be responsible for keeping up with safety regulations, code and standards compliance, arc-flash analysis maintenance, regular PPE and LOTO inspection and maintenance, training, facility rules, and regular audits.
The most important things to remember when working on energized equipment are:
- Is it necessary? If the work can be avoided or postponed, it should. This is a team decision, not a top-down mandate. If powering down is not a possibility, the component should be isolated form the electrical current using breakers and switches. Unfortunately, legacy systems do not allow for isolation of components.
- LOTO (lock out, tag out) must be properly implemented. Equipment that can be turned off or isolated must be in a safe position, with a proper tag and proper lock. Only the person who placed the lock should be responsible for removing it.
- Properly marked work zones (Flash protection boundary, Restricted approach boundary, Limited approach boundary, and Prohibited approach boundary) must be observed and respected.
- When work is completed, the whole team must assemble to determine that it is done and all tools and personnel are secure before returning equipment to operational status.
Many Data Centers choose to outsource their electrical maintenance, a good option since most electricians will be familiar with the risks involved and proper precautions that need to be taken. Facilities should provide an escort for new vendors, however, to ensure they are compliant with Federal regulations and facility rules. Never assume that just because an electrician is licensed they will be compliant and competent. The risk is too great.
To find this information about Arc Flash and other Data Center hazards and more, consider attending the past Webinar on the topic at Mission Critical Magazine. Also, see additional resources below on this important issue.
Online handbook on electrical safety from Littelfuse.
Facilities Management podcast on Data Center fire safety.
Electricity Forum information on PPE.
Next in the Solutions Series: Time Delay Interference in Simulcast Systems
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