Emergency Lighting Tips by Electrical Products and Solutions

Exit Signs and Emergency Lights can be purchased at the EXIT STORE for up to 60% off retail.

We stumbled accross this interview and found it to be a very helpful summarization to the types of questions we get asked often at The Exit Store. This interview comes from the magazine Electrical Products and Solutions. You can find this article and many others like it within the archives. Here is the link to the archives, as well as, the link to this particular interview.
EXIT SIGNS, EMERGENCY LIGHTING, AND THE QUESTIONS YOUR CONTRACTOR SHOULD KNOW THE ANSWER TO

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Q & A: Insights into Emergency Lighting

In this interview, Paul Markee offers helpful information about emergency lighitng for contractors.

Q: What are important insights in implementing emergency lighting that contractors may not know?

A: Frequently, installers and designers refer to egress lights and emergency lights as if they are interchangeable terms; which is incorrect.

Egress lights are fixtures connected to the normal power supply system and are to function at all times when the building is occupied.

Emergency lights or stand-by lights are normally battery-type emergency unit equipment that provides no illumination until failure of the egress lighting circuit. These units serve as a backup for egress lights.

Exit signs and emergency exits must indicate all exits and emergency exits. Where it is impossible to obtain direct line of sight to an exit, or where there could be some doubt as to the direction of the exit, the words “EXIT” or “EMERGENCY EXIT” must be accompanied by directional chevrons. The idea is to direct someone who is not familiar with the building to an exit. All these signs must be illuminated at all times so that they are legible.

Q: What are some of the illumination requirements for emergency lighting applications?

A: There are numerous factors to take into consideration when looking at emergency lighting illumination. As stated in the Life Safety Code (NFPA 101) 7.9.2.1; “Emergency illumination shall be provided for not less than 1-1/2 hours in the event of failure of normal lighting. Emergency lighting facilities shall be arranged to provide initial illumination that is not less than an average of 10.8 lux (1-ft-candle) and, at any point, not less than 1.1 lux (0.1 ft-candle), measured along the path of egress at floor level. Illumination levels shall be permitted to decline to not less than an average of 6.5 lux (0.6 ft-candle) and, at any point, not less than 0.65 lux (0.06 ft candle) at the end of the 1-1/2 hours. A maximum-to-minimum illumination uniformity ratio of 40 to 1 shall not be exceeded.”

Q: What is an important factor for implementing good quality emergency lighting?

A: An important guideline for emergency lighting implementation is in the wiring. The National Electrical Code (NFPA 70) Article 700, states that the “wiring of two or more emergency circuits supplied from the same source shall be permitted in the same raceway, cable box or cabinet. Wiring from an emergency source or emergency source distribution overcurrent protection to emergency loads shall be kept entirely independent of all other wiring and equipment, unless otherwise permitted in [1] through [4]: [1] Wiring from the normal power source is located in transfer equipment enclosures, [2] Wiring supplied from two sources in exit or emergency luminaries (lighting fixtures), [3] Wiring from two sources in a common junction box, attached to exit or emergency luminaries, [4] Wiring within a common junction box attached to unit equipment, containing only the branch circuit supplying the unit equipment and the emergency circuit supplied by the unit equipment.”

Article 700 also state the “no appliances and no lamps, other than those specified as required for emergency use, shall be supplied by emergency lighting circuits.”

Unit equipment must be permanently mounted in place with the wiring for the units installed in accordance to Chapter 3 of the National Electrical Code. Cord and plug connections are permitted, but must not exceed three feet in length.

Q: How can contractors help their clients understand emergency lighting?

A: Contractors can help educate their clients about emergency lighting systems that are installed in their facilities. Many end-users do not realize that the systems in their facilities must be maintained and inspected monthly. An understanding of the testing requirements from the Life Safety Code (NFPA 101) 7.9.3.1.1 is critical. As stated in the code, “Testing of required emergency lighting systems shall be permitted to be conducted as follows: [1] Functional testing shall be conducted at 30-day intervals for not less than 30 seconds. [2] Functional testing shall be conducted annually for not less than 1-1/2 hours if the emergency lighting system is battery powered. [3] The emergency lighting equipment shall be fully operational for the duration of the test required by 7.9.3.1.1(1) and 7.9.3.1.1(2). [4] Written records of visual inspections and tests shall be kept by the owner for inspection by the authority having jurisdiction. The same guidelines are to be followed for exit signs.

There are many options available for emergency lighting systems that can make the inspection process easier and less time consuming for the end-user. Examples of such options are remote testing, self-test/self-diagnostic as well as computer-based testing. However, these options are must be utilized in the manner in which they have been intended.

There are also issues in buildings with open-plan offices that have had floor layouts reorganized to form new aisles and exit routes, but the emergency lighting is not changed. As a result, when the power fails, the original egress routes are blocked by walls and privacy panels and the new egress routes are not properly illuminated.

Q: What are some new trends in emergency lighting?

A: One growing trend in emergency lighting is low-level signage. A remote exit sign is mounted about 6 inches from the floor level and is used in conjunction with the exits located at ceiling height. This trend has occurred to accommodate the fact that smoke usually rises, thus getting down to floor level will generally place people in clearer air as well as a clear path to the exit.

Another trend that as been seen in some jurisdictions is the requirement of exterior egress lighting. So, not only does the path to the exit need to be illuminated, but the path leading away from the area. Some jurisdictions are also taking the Life Safety Code’s illumination levels from the 1 ft-candle average to a 1 ft-candle minimum.

There still is a controversy regarding the color of exit signs. Should it be red or green? NFPA 101 states that exit signs must be a “distinctive color”. However, Regional/National Building Codes might be more specific than NFPA 101, thus leading to certain areas having red signs and others having green. There are many theories on red vs. green. It has been said that green exits are easier to read since the human eye cannot see red light as easily, especially through smoke; green signs will never be confused with actual fire itself and that the color green has positive psychological and emotional effects on people as compared to red.