Impacts of Flooding on Elevators

It is common to find water in elevator pits. A continuous influx of water is possible, especially to pit bottoms that start below ground level. Also, external factors, such as natural disasters, excessive precipitation and storms, can cause an influx of water into buildings, flooding the pit bottoms. But what are the impacts of exposure to water on the security and equipment life of the elevators?

There is no requirement for manufacturing waterproof electrical equipment for the elevators, except for firefighters’ lifts. Basically, all the components except electrical equipment at the pit bottoms of firefighters’ lifts are protected against dripping or sprinkling water. Therefore, there is no special protection against flooding for elevators manufactured in accordance with regulations and standards.

In cases of water in the pit, according to the annex of periodic control, a blue label is attached to the elevator. It indicates that the elevator is slightly faulty, and it can be used in 12 -48 months. The presence of water in pits may create the risk of short circuits in electrical components. In case of a short circuit, current should be cut off at the power switches but, due to high instantaneous current, the paths on the electronic cards may burn and the elevator may become nonfunctional. So, the components at the bottom of the pit are under great risk because the safety contacts are placed at the bottom of the pit. A short circuit on the safety contacts may burn the main board on the terminal box placed over the cabin where the inputs and the outputs of the contacts are, and the main board on the controller.  In terms of human health, instantaneous short circuits may cause electric shock, especially in the installations where ground residual current relays are not available or are not working. Additionally, water intrusion in elevator installations decreases the insulation resistance. In a healthy installation, when the contacts are open, an infinite resistance is measured between the ground and the live conductors under 500V, while the resistance value in installations, which are continuously exposed to humidity, decreases to kilo-ohms. The decrease of insulation resistances means there is a risk of uncontrolled energy in the system, which in extreme cases exposes users to electrical currents.  

To prevent damage caused by water penetrating into elevator pits, it is useful to apply a series of measures. The first measure is to build a water outlet or catch drain together with the pit. Although drain pumps placed at the bottom of the pits are considered to be foreign installations by some inspection organizations, their presence is not contrary to the standard since this equipment is used only for elevators (except emergency elevators).  Additionally, holes covered with portholes may also collect the water at a certain place and prevent damage to a certain degree.  

To minimize damage caused by flooding, all components used at the bottom of the pit should be certified to the minimum IP 67 waterproof.  As the components used at the bottom of the pit, such as safety contacts, sockets and switches, are relatively cheap, by paying a little more money we may protect the elevator from greater risks. If the water enters the pit from the floors, ceilings or air wells, switching the elevator off and putting it out of service, disconnecting the battery connections and lowering the main fuses would be the safest protection method.

Apart from instantaneous influx of water, if there is a continuous influx of water, or if there is always a presence of water at the bottom of the pit, the amount of moisture content in the pit greatly increases. In this case, both the electrical and mechanical equipment are affected. As the temperature differences sometimes vaporize the humidity in the pit, electrical equipment may be affected because of short circuits of the paths in electronic cards and on/off switches. On the other hand, mechanical equipment is exposed to corrosion and comes to the end of its lifecycle earlier. Corrosion, which is especially a problem in landing door locks, creates a permanent failure, as the safety circuit is opened because of the inability to transmit electrical current. Corrosion of the ropes requires costly replacements after a short period of time. Therefore, if an elevator is to be installed where it is likely to operate in conditions of high humidity, stainless steel capacity should be 304 or its derivatives, while IP X6 or higher insulation should be used for landing door contacts and other safety contacts. The life of the components in pits where it is impossible to prevent water intrusion and humidity can be extended by painting the brackets and welding points with an anti-rust paint, using lighting installation in IP X6 or higher class, and keeping electronic cards and wiring in boxes so as to be protected from direct contact with water.  

Measures that will be taken after flooding

If an elevator has encountered extensive water damage, it will need maintenance and inspection before it can be returned to use. Contacts that have lost their conductivity, water-soaked electronic cards and droplets that have penetrated into the connection terminals can cause the elevator to be severely damaged, both in the short term and the medium term. 

During the first maintenance, the water in the pit must be evacuated and the controller, driver, safety contacts, overhead connection terminals and cards, buttons and indicator installations, all related cabling, pit bottom safety contacts and lighting installation should be inspected. In fact, the aim with this kind of equipment should be to re-implement them after drying and testing. Partial implementation may also be one of the methods. For example, the lighting installation, safety circuit and controller-driver-motor implementations, as well as the battery feeds, may be energized separately so impacts of a possible short circuit on the other electrical components can be prevented. Before reactivation, the insulation and continuity tests defined in EN 81-20 Chapter 6 should be repeated so that it is possible to be protected from being exposed to insulation resistance of live conductors and the risk of being exposed to current, which can directly affect the users. These tests should be carried out according to the instructions given by the manufacturer, and the test results should comply with the HD 60364-6 standard referenced in EN 81-20. Implementing the elevators after all tests are complete and observations are made is a necessary method to be protected from instantaneous damages caused by water and in disputes that may arise with the maintenance institution.

Of course, the failure of elevators due to natural disasters is inevitable; however, it is possible to minimize the damage with low-cost measures taken before and after disasters and through following an implementation process.