Emergency lighting: types, requirements, device, circuits, health check

If in the event of a power outage for household consumers the problem does not pose a big threat, then in emergency conditions at large industrial facilities, organizations and crowded places, the risk of incidents and injuries is possible people. Emergency lighting is used to prevent such situations.

The main objective of such lighting installations is to create the minimum required level of visibility on the stairwells, at the exits, near hazardous facilities and in other rooms. In order to ensure safe evacuation of personnel or visitors in the event of a power outage.

Types of emergency lighting

Depending on the assigned tasks, such installations can perform certain functions - some act as alarms of passages, others maintain the necessary level of illumination to perform any technological processes. According to the requirements of SNiP, which regulates the norms of illumination, emergency lighting is divided into two types: emergency and backup.

Evacuation lighting

Evacuation lighting is considered to be such a category of devices that is installed in cramped rooms, walkways, outside buildings for the safe exit of people. This category of lighting devices is switched on in case of breakdowns, in case of fires, onset natural disasters that caused the subsidence or complete absence of the main source power supply.

Be sure to install:

• In walkways and stairs, at evacuation exits, if the calculated number of people moving along them in an emergency is 50 or more.
• In buildings with 6 floors or more.
• If the number of employees is more than 100, the placement of lamps should be performed in all industrial premises where there is an increased risk of injury and along the route staff.

For the correct operation of such lighting installations, special technologies and connection schemes are used.

Safety Lighting (Standby)

Back-up lighting is considered to be such a category of lighting equipment that, in the event of a main power failure continues to illuminate production areas that pose a potential threat of accident or in which strict compliance with fire regulations is required security.

This includes technological processes that must be completed, even in emergency situations, for example, at power plants, pumping stations, communication centers, child care facilities and others. Therefore, safety lighting should provide sufficient conditions for the performance of certain operations in the workplace.

It should be noted that such artificial lighting is mandatory for preschool and school organizations, regardless of how many people are in them.

Distinctive features of European standards.

According to EN-1838, evacuation lighting is divided into three more categories:

1. For rescue routes - provides for the ability to safely leave the production area on the established route;
2. Panic lighting - provides the ability to get to the exit from places of large crowds, for which emergency lighting is used;
3. For highly hazardous areas - is installed near machines and mechanisms with rotating or other dangerous elements, in the event of the disappearance of working lighting near which there is a danger of injury.

When comparing the other separation criteria for SNiP and EN presented in Figure 1, you can see their identity with respect to the main types of emergency lighting.

Requirements and Regulations

The main regulatory documents regulating the requirements for the device and operation are - GOST R IEC 60598-2-22-99 for lamps for emergency lighting; GOST R 55842-2013 (ISO 30061: 2007), SNiP 23-05-95 in the scope of the relevant section; Electrical Installation Rules in the scope of the relevant chapter. They indicate the requirements for the luminaires themselves, as devices, give a classification of devices and establish the rules for placement, connection to the electric network, and the norms for their normal operation.

Based on the above documents, the following regulatory requirements are imposed on emergency lighting devices:

• Autonomous food should provide illumination of areas for movement in the room from 0.5 lux, and in the open space from 0.2 lux.
• Due to the uneven placement of lamps or LED lights, the uneven level of illumination along the axis of movement should not exceed the ratio of maximum to minimum - 40: 1.
• In rooms it is allowed to use safety lamps for power supply from reserve sources as evacuation ones.
• The use of evacuation signs is a mandatory norm for such walkways and exits from buildings, where at the same time there may be 100 or more workers. And in cases when there is no natural lighting, the minimum number for installing light indicators is reduced to 50 people. The same requirements apply for rooms over 150 m2.
• In addition to the light, you can install signs that do not themselves burn from autonomous power, but are lit by emergency lamps.
• The overall dimensions of the signs should ensure their sufficient visibility, and the distance between them should not exceed more than 25 m. In addition, they are placed at bends at junctions of other rooms, entrances and exits.
• It is allowed to install both working only in standalone mode, and supporting combustion in conjunction with centralized power supply.
• Security lighting, as an emergency option, can be performed by any lighting devices, except for those options when the light is turned on only when it is triggered. Then for electrical installation only incandescent lamps can be used.

Depending on local conditions, one of the methods of connecting and implementing the system may be used.

Device and circuit of emergency lighting network

Such schemes necessarily include three main elements - an autonomous power source, lighting devices and switching switches. The latter carry out switching between two power sources - main and emergency.

A power circuit with various light sources is used for low power facilities.

These include: Incandescent lamps L (1 main and 2 emergency lights), relay contacts K, fuses Pr, rectifier B and battery AB. When the main power is turned off, the relay switches, and the emergency lights are powered from the battery installation.

The emergency circuit includes incandescent lamps of much lower power than the main ones, because their task is to ensure minimal illumination. And the rectifier is designed to continuously charge the battery in normal mode. The advantages of such a scheme are that the main lighting can use fluorescent lamps, LED lamps or housekeepers.

A single-source power circuit (Figure 4) is best suited for applications where power failure of electrical installations must provide the same level of lighting as with normal mode.

Please note that here the lamp is powered from the main power source in normal operation, and if there is no voltage on it, the relay contacts transfer the same lamp to the battery nutrition. The autonomous source itself is also constantly recharged from an external network, as in the previous version, through a rectifier device. The disadvantage of this scheme is the huge cost of electricity to power incandescent lamps.

The solution to this drawback for large facilities and industrial enterprises is possible when the inverter is included in the emergency power circuit.

Look at Figure 5, here the direct current is converted, which comes from the power supply into alternating current, which allows you to turn on any type of lamp.

The practical application of one or another scheme must be carried out on the basis of a detailed analysis of working conditions, the power of lighting devices and production features. Also consider how to lay lines for power and their type.

Technologies and equipment for emergency lighting

Emergency lighting technologies provide two options for the operation of lighting devices: those that are turned on only in case of emergency and those that are constantly on. The first of them work from a signal coming from an additional wire that is connected to the distribution panel. It transfers the potential to the logic unit, which ensures that the relay is held in the position of the main lighting, due to which the emergency is in the off state. If the voltage in the switchgear disappears in the additional wire, the potential disappears and the relay switches the lighting to emergency.

The second technology offers LED models powered by a stand-alone battery. Due to their low power, they do not burn out and boast a long service life.

Health check

Both during commissioning and during operation, such a system must be tested for serviceability. Two options can be used for this - local and central.

1. Local monitoring provides for the possibility of checking each device in turn. Of course, such a method is only advisable for objects with a small area, where it is possible to get around each lamp. In this test, a manual test function is used, which is built into some types of equipment or the corresponding button. They forcibly turn off the main power and give a signal on the board or indicator on the health of the device.

The disadvantage of the local method is local features, when uncomfortable placement: clutter or high location create difficulties for verification.

2. Central monitoring collects health information from a group of devices. Why use data cables, existing logic circuits or wireless channels. The formation of such a monitoring system is appropriate at large industrial or strategic facilities. The advantage of central monitoring is the speed of testing for automatic inclusion, the ability to obtain detailed verification data and reporting.

Based on the results of the check, an act is compiled with data on the test of each lamp. If problems are identified, they are eliminated, after which a second test is carried out. Commissioning or subsequent operation with faulty elements in the system is not allowed.