Safety in elevators
Background of elevators
Safety in elevators has always been a major concern for building owners and managers. In 1854, Elisha Graves Otis solved the safety problem by introducing the first safe elevator. The innovation entailed the incorporation of guide rails that protected the elevator from plummeting back to the hoistway pit. According to Hempstead and Worthington (879), the innovation of the elevator revolutionized modern architecture by making it possible to move materials and people in tall buildings, which was previously impractical.
Elevator designers have developed different designs and control systems to improve efficiency. However, one of the issues that continue to be a great concern relates to elevator safety. This paper entails comprehensive research on safety in elevators coupled with an evaluation of the various safety devices incorporated in elevators such as governors and safeties.
Components that enhance elevator safety
A number of safety features are incorporated in the process of designing passenger elevators. The objective is to safeguard the public against possible harm that might arise in the process of using elevators. On the other hand, freight elevators have the capacity to handle heavy loads moving horizontally across the elevator floor. Few safety features are incorporated in freight elevators compared to passenger elevator, which means that freight elevators pose a great safety risk to the public. Elevators are fitted with a number of devices that aim at increasing public safety. Some of these devices include hoist-way, machine rooms, elevator cabs, entrances, and door equipment (Craighead, 266).
Hoistway/ elevator shaft
This refers to the guide rails on which the elevator moves up and down during its operations. To increase elevator safety, the hoistway is fitted with a buffer, which protects the elevator from descending to the elevator pit by acting as breaks. An elevator pit is a term used to describe the bottom side of the hoist-way.
Machine room
This refers to a room that contains different mechanical equipments, which makes it possible for the elevator to move up and down. Some of the equipments fitted within the machine room include “controllers, pumps, hydraulic tanks, and hoisting machines” (McCain 38). Equipments within the machine room are fitted with safety equipments and perform different functions. For example, the controller controls the speed, direction, location, and the stopping point of the elevator.
The controller also regulates the opening and closing of the doors, indicating to the passengers the position of the elevator in the hoist-way and indicating the direction towards which the elevator is moving. In case of emergency, the machine room is used in operating the elevator (Grondzik, Kwok, and Stein 49).
Entrance
This refers to every stop that the elevator makes in the course of traveling up and down a building. Some of the elements that make up the entrance include the hall buttons, doors, and frames.
The elevator cab
This refers to the “section in which the passengers ride in” (McCain 26). The elevator cab is composed of a number of indicators and control features. Some of these features include the emergency lighting, car-operating panel, and the door operator. Emergency lighting provides lighting in the event of power loss, for example, electrical blackouts. The car-operating panel is composed of the floor buttons that the passengers use to designate the floor they intend to move to as their destination. It is important for elevators to be fitted with a telephone component for passengers to use when seeking help in the event that they are trapped in the elevator (Standiford 386).
The elevator doors are fitted with safety devices that prevent them from closing on equipments or passengers on their entrance (Goodwin 16). One such elevator door safety device that is used in older elevator systems includes the use of a mechanical edge, which pulls back the door if it comes in contact with an object that blocks it from closing. Consequently, a signal is transmitted to the elevator controller, and the door is re-opened. Newer elevator systems are fitted with infrared ray beams. The infrared beams form a network at the elevator entrance. If an object at the entrance obstructs one of the infrared ray beams, a reverse signal is transmitted to the elevator controller.
Governors and safeties
There are different types of elevators, which have been designed to assist in vertical movements. The two main types of elevators include traction and hydraulic elevators. Hydraulic elevators are fitted with hydraulic devices, which include a pump and a cylinder. These components make it possible for the elevator to move passengers and equipments up and down buildings. In most cases, the hydraulic cylinder is filled with oil that is pressed by a pump to the cylinder.
Traction elevators travel up and down buildings using cables. To increase its safety, the traction-elevator machine room has a number of safety devices. Some of these devices include the controller and the hoisting machine and brakes. An over-speed governor is also fitted in order to control the speed of the elevator. Moreover, the over-speed governor is automatic to ensure effectiveness in controlling elevator speed.
If the elevator is traveling at a very fast speed, the governor disconnects the power supply to the motor. However, if the speed does not reduce, the governor engages the safeties. The safeties are clamps that firmly grip onto the guide rails, and thus the speed of the elevator reduces successfully. In modern elevators, the elevator only travels a few feet at high speed when the safeties come into play. For the elevator to function again after engagement of the safeties, they have to be reset (Strakosch and Caporale 45).
Testing
Governors and safeties should undergo periodic testing to ensure that they are functioning properly. The tests ascertain that the elevator can function appropriately in the event of a real emergency. There are two types of tests to determine the safety of the elevator. They include a full-load test and no-load test. In no-load testing, no weight is added to the elevator. The elevator is allowed to take a free fall.
The objective is to examine whether the safety clamps will be activated and grip the guide rails, thus stopping the elevator. On average, no-load testing should be conducted annually. On the other hand, full-load testing occurs by loading the elevator cab with the elevator’s rated weight capacity. The elevator is then allowed to take a free-fall to examine how effective the safety devices are working at full-load. This test should be conducted every 5 years (Kiritsis 65).
Firefighter’s service
Elevators are also fitted with signs warning the public not to use the elevator in case of a fire for the elevator may stop at the floor on fire thus threatening the safety of the passengers and their property. To prevent this scenario from happening, the involved authorities have incorporated a number of national safety standards on elevators. For example, elevator designers are required to incorporate special elevator operating systems, which should be activated in the event that a fire breaks out. Additionally, only trained fire fighters should use the elevator in the event of a fire.
Smoke detectors are fitted at different points such as the hoist-way and the landing position of the elevator in each floor. The detectors are connected to the controller. The smoke detectors function is to trigger the fire fighting service. Therefore, the elevator fire-detection system should not be connected with the building’s fire-detection system. Upon detection of smoke, the elevator should travel to the lowest landing point to allow passengers exit the building.
If this scenario occurs, the elevator should not travel again to prevent passengers from being trapped in the building. The elevator has to be reset to travel up the building again (Kiritsis 65). The second phase of the elevator fire fighting service provides trained personnel and fire fighters with an opportunity to travel to the upper floors. A special key, which allows the elevator to move up the elevator to a point closer to where the fire has been detected, is triggered to perform this function,
Single-bottom cylinder failure
Earlier versions of hydraulic elevators may pose a safety hazard to passengers if the piston or cylinder corrodes. The probability of this occurring is relatively high because the cylinder and piston are buried in the ground. The minerals, water, and metals in the cylinder may react resulting into electrolysis. The electrical charges cause the cylinder to corrode thus creating holes. Oil leakage may cause the elevator to experience disastrous failure; for example, it may descent uncontrollably leading to loss of life and damaging of buildings (Kiritsis 65).
Levelling
One of the major sources of safety hazard to passengers using elevators relates to levelling. Levelling occurs when the elevator fails to move up to its normal landing position and stops at a point slightly higher or lower its designated landing point. If this occurs, passengers may trip and fall or even experience severe injuries. A standard requiring elevators to level at 0.25 inches of the floor level was formulated to prevent such accidents from occurring
Conclusion
The analysis of safety in elevators has illustrated that elevators can pose a serious safety threat. Consequently, it is important for the appropriate safety devices and components such as governors and safeties to be implemented. The safety devices should be effective in controlling elevator movements and speed. Frequent tests to evaluate the safety of the elevator should be conducted. To ensure passenger safety in the event of a fire, fire fighter’s services should be incorporated in the elevator. It is also vital for hydraulic systems in elevators to be checked regularly to determine their effectiveness. Finally, elevator manufacturers should ensure that they comply with levelling requirements to minimise occurrence of safety hazards.
Elevator and escalator maintenance contracts
Background information
An escalator is another method designed to aid in vertical movements within buildings. The only difference with elevators is that escalators’ vertical movement is only for a short distance. Escalators are made up of different components, which include the controller, chains, handrails, and truss. Similar to elevators, escalators are fitted with numerous safety devices. The basic safety devices incorporated in escalators include demarcation lights and emergency stop switches.
Demarcation lights are positioned at the bottom and top of the elevator and they function to indicate to the passengers the exit and entry points. This aspect increases the passengers focus on safety while on the escalator. On the other hand, the emergency switch is used to stop the escalator in case of an emergency.
According to Craighead, safety in escalators and elevators is a complex issue (35). Therefore, it is paramount for effective maintenance to be undertaken on the various elevator and escalator safety devices. This section aims at illustrating various issues associated with elevator and escalator maintenance contracts. This section takes into account the three main types of escalator and elevator maintenance contracts, which include lubrication and inspection, full maintenance and inspection, and lubrication of small parts.
Lubrication and inspection contracts
These contracts provide little coverage to elevator systems. The contract requires a mechanic to make frequent visits to check the various elevators and escalator equipments. The visit intervals may be monthly, semi-annually, quarterly, or annually. The limitation of these lubrication and inspection contracts in guaranteeing escalator safety is that the mechanic only undertakes visual inspections. The escalator is not dissembled.
However, the accessible moving parts are then lubricated using grease or oil. This means that if lubrication cannot be performed on parts that are not accessible. Upon conducting the inspection, the mechanic is required to draft a list illustrating other areas that require maintenance and present it to the property owner. The responsibility to schedule the date for carrying out repairs then rests on the property owner. However, the repairs come at an additional cost.
Jarboe asserts that this form of maintenance is most suited for modern hydraulic elevators compared to old hydraulic and traction elevators (23), for they are not composed of small and numerous moving parts. Traction and older hydraulic elevators are expensive to maintain using this type of maintenance contract. This argument arises from the fact they contain numerous moving parts. Additionally, the fact that these elevators are controlled electronically increases the suitability of this type of maintenance contract. They also expose the owner to a high degree of liability in the event of an injury occurring (McCain 25).
Consequently, this form of elevator maintenance contract is not appropriate for escalators. The short-term cost of this type of maintenance contract is relatively low. However, the long-term cost of undertaking maintenance may complicate the budget because they tend to be high.
This type of contract is also associated with intensive paper work because the property manager or owner has to coordinate with all the maintenance activities undertaken by the elevator maintenance company. Another disadvantage of this elevator maintenance contract is associated with the fact that any liability that might arise in the course of using the elevator rests on the property owner or manager because the building owner has the responsibility of ensuring that the elevators are functioning properly.
Lubrication, inspection, and small parts contract
This contract is similar to the lubrication and inspection contract for it takes into account similar inspection and lubrication equipments. The only difference is that this contract integrates minor repairs and adjustments conducted on small parts in the elevator. The contract specifies the parts of that the elevator company is responsible of maintaining. The contract also integrates a number of trouble calls, which refers to calls for service in case of the elevator or escalator malfunctioning.
Building managers and owners should have a clear understanding of what the terms ‘minor’ and ‘small repairs’ constitute. This element arises from the fact that some of the problems that the elevator might experience may not qualify as minor problems, which means that an additional cost may be incurred to maintain the elevator. McCain asserts that this type of maintenance contract is not suitable for escalators due to their complexity and the liability associated with them (46). Currently, most elevator-maintenance companies are not offering this type of contract. This arises from the fact that they tend to incur high costs.
Full-maintenance contract
According to Kiritsis, full maintenance contract assigns the elevator manufacturing company the total responsibility of ensuring the elevator equipments are functioning properly (65). As a result, this type of contract takes into account a number of escalator and elevator maintenance activities such as inspection and lubrication. The contract also covers other malfunctions that might arise due to elevators and escalators’ wear and tear. The number of maintenance calls in this type of maintenance contract is not limited. However, the calls have to come during the normal working hours.
One of the benefits of full maintenance contract is that it gives building managers an opportunity to budget the annual cost of maintaining the elevator effectively. Additionally, this contract also safeguards building owners and managers from possible liabilities that might arise in the event of the elevator malfunctioning. Consequently, the elevator contractor carries the responsibility of determining the number of annual maintenance visits to assess the safety of the elevator.
Contract options
Different elevator coverage options are in place to provide the desired escalator and elevator maintenance. One of these call options is the overtime callbacks, which provide building owners and managers an opportunity to call for assistance in case of an emergency outside the normal business hours. A higher cost is associated with this contract option, which makes it to be appropriate for full-maintenance contract.
Other elevator-maintenance coverage options provide building owners with a discount with regard to billing terms and elevator monitoring. Some elevator companies automate their elevator systems making it possible to identify possible malfunctions and ensure effectiveness. This plays a significant role in minimising maintenance for the elevator company. Other contract options provide building owners with discounts by taking into account their billing systems. The billing system may be monthly, semi-annually, or quarterly.
Conclusion
The above analysis illustrates the importance of ensuring safety in escalators and elevators, which has led to the emergence of numerous elevator maintenance companies. These companies offer building owners and managers with an opportunity to select their desired elevator and escalator maintenance contracts. The three main types of contracts include lubrication and inspection contracts, full maintenance contracts and lubrication, and inspection and small parts contract.
The lubrication and inspection contract provides building owners and managers with minimal elevator safety coverage in that they only conduct visual inspections on elevators. Only the accessible moving parts of the elevator are lubricated meaning that the elevator is not fully maintained. Consequently, the building owners incur additional cost if full maintenance is to be undertaken. The owner is also exposed to possible liabilities that might arise if the elevator or escalator malfunctions.
On the other hand, lubrication, inspection, and small parts contract covers minor repairs and adjustments in addition to lubrication. Additionally, the owner can undertake trouble calls in case of an emergency. However, the limitation of this contract is that liabilities arising from malfunctioning of the elevator and escalator rest on the owner or property manager. With regard to full maintenance contract, “the elevator maintenance company is charged with the responsibility of total maintenance of the elevator and associated liability” (Standiford 385).
As a result, the building owner or manager can manage to budget the cost of maintaining the elevator. Elevator maintenance companies have developed different contract options to take into account customer desires, and to ensure effective elevator maintenance, building owners should adopt full-maintenance contract.
Elevator-maintenance contract management
Background
Elevator maintenance is one of the issues that have become of great concern to owners of tall buildings. This aspect arises from the fact that failure of the elevators can cause building owners to incur substantial financial cost if sued for loss of property or life. Due to the lucrative nature of the industry, numerous elevator maintenance contractors have emerged, which presents a challenge to building owners with regard to selection of the contractor. As a result, it is important for building owners to undertake elevator contract management. A number of issues should be taken into account to achieve this goal. This section entails a comprehensive analysis of elements associated with elevator-maintenance contract management.
According to Kiritsis, building managers and owners should obtain a minimum of three bids from well-established elevator maintenance companies (55). The objective of obtaining three bids is to provide building owners and managers with an opportunity of evaluating and comparing the maintenance proposals. Property owners can thus select the most effective elevator maintenance company. During the evaluation phase, a number of elements should be examined. Some of these elements are outlined below.
Billing terms
Some of the elements taken into account in the billing terms include the price and the frequency within which the client will be invoiced. Therefore, it is important for the elevator maintenance companies to breakdown the maintenance price into similar units in their proposals. The price units may be either monthly or quarterly. It is also important for the manager to assess the rate of adjustment (Hempstead and Worthington 879).
Some elevator maintenance companies undertake their billing monthly. Most elevator-maintenance companies that offer full maintenance operate in a similar manner to insurance company. As a result, they require building owners to pay their maintenance cost in full every month. Other billing companies require property owners to pay a three-month maintenance cost. Managers should understand the billing system that the maintenance company adopts to ensure effectiveness in making the payment. Some elevator maintenance companies require electronic payments.
Contract length
This refers to the duration within which the contract will last. Most common elevator maintenance last for one, two, or five years. In managing elevator maintenance contracts, it is critical for building owners to determine whether the contract has a provision requiring the elevator company to make a refund in event of skipping or failure to undertake complete maintenance.
Some elevator maintenance companies may offer their clients terrific contract prices; however, they may not be effective in undertaking the maintenance. Consequently, numerous complaints from customers arise due to unusual vibrations and noise. If the owner has entered in a long-term contract with the maintenance and it does not respond to calls to rectify the problem, the building owner may be trapped in such a contract. Therefore, it is important for building owners to ensure that they enter into short-term contracts.
Cancellation policy
This policy stipulates the rules and regulation that customers should follow if they wish to annul the contract. In some countries such as the United States, elevator maintenance contracts are allowed to automatically ‘roll-over’. This means that they join with other contract cycles. The contract holder can cancel the contract within the acceptable period. In most cases, the contract holders are required to issue 90 days notification. Building owners should keenly evaluate the contract cancellation policy because the cancellation policy may contain some clauses, which if breached can lead to property owners incurring heavy financial cost. Some elevator maintenance companies may not include the policy cancellation clause in the contract. If this happens, it is important for building owners and managers to inquire about the same.
Parts and systems covered
Property owners and managers should conduct a comprehensive evaluation of the maintenance contracts. This will aid in pointing out some parts of the escalator and elevator that are not covered. One of the elements that building owners should take into account is the price. If the price of a contract is too low, then the probability of the contract excluding some parts of the elevator is high.
Visit frequencies
Property owners should compare the contract bids to determine the degree of coverage and the number of visits that the mechanic will conduct to assess the safety of the safety.
Trouble calls
Considering the fact that elevators and escalators may malfunction frequently, it is important for building managers to assess the number of times that they can call the elevator maintenance company to come and rectify the problem. This assessment is critical because different elevator management companies provide different trouble calls for different contracts. Additionally, managers should also evaluate whether the trouble calls are a part of the monthly service call. Another issue that should be taken into account is the duration within which the maintenance company should respond in the event of passengers and equipments being trapped.
Insurance covers
Building owners carry the responsibility of ensuring that passengers are safe in the process of using lifts. Therefore, one of the issues that they should consider relates to whether the contractor has purchased inclusive insurance cover, which aims at covering passengers from loss that might arise in case of an emergency.
Sufficient technical knowledge and responsibilities
Considering the high rate of innovation with regard to designing and manufacture of elevators, it is important to determine whether the proposed elevator maintenance company aligns itself with changes in the elevator industry. One of the issues that should be considered relates to the experience of the maintenance company for this aspect will aid in making informed decision when selecting the contractor.
Additionally, it is important for clients to evaluate whether the maintenance company has sufficient knowledge with regard to operation of the elevator. Another issue that should be considered relates to whether the elevator manufacturer will offer the contractor with the necessary technical support. The contract holder should determine whether the responsibility of cleaning elevator car, lift pit, machine room and other safety components rests on the contractor.
Spare parts
During the maintenance process, the contractor will be required to replace the worn out parts. The effectiveness of the elevator’s operation after undergoing maintenance is dependent on the type and quality of the spare parts used. Building owners and managers should ensure that their contractors have adequate spare parts. They should also ascertain the model and brand of the spare parts to prevent the lift from malfunctioning after undergoing maintenance. One of the ways through which this can be attained is by conducting visits to the contractor’s premises to confirm the presence of the spare parts. It is also important for clients to inquire about the time taken for the spare parts to be delivered.
Ability to deal with emergencies
Building owners and managers are faced with a liability in the event of their buildings’ elevators failing. Therefore, it is important to manage the contractors’ response to emergencies. One of the ways through which this can be undertaken is by setting the time limit in the contract within which the contractor should respond. It is also important for clients to assess the geographical location of the contractor.
Conclusion
The above analysis has shown that building owners and managers should take into account a number of issues when managing elevator maintenance contracts. Some of these issues relate to contract length, parts covered, cancellation policy, and billing terms. Other issues that should be assessed relate to trouble calls, insurance covers, and number of visits to assess the safety of the elevator. The manager should also evaluate the effectiveness of the contractor in undertaking maintenance activities in addition to responding to emergency activities.
Works Cited
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Goodwin, Jason. Otis: Giving rise to the modern city. Chicago: Dee. Print.
Grondzik, Walter, Alison Kwok, and Benjamin Stein. Mechanical and electrical Equipments for building. London Cengage Learning, 2001. Print.
Hempstead, Colin, and William Worthington. Encyclopedia of 20th century Technology. New York: Taylor and Francis. Print.
Jarboe, Theodore. Elevators and escalators rescue guide, Oklahoma: Fire Engineering Books. Print.
McCain, Zack. Elevators 101. 2nd ed. Alabama: Elevator World, Inc., 2007. Print.
Kiritsis, Dimitris. Engineering asset lifecycle management. London: Springer-Verlag, 2010. Print.
Standiford, Kevin. RCA: Facilities maintenance, Clifton Park: Cengage Learning, 2010. Print.
Strakosch, George, and Bob Caporale. The vertical transportation handbook, New York: John Wiley & Sons, 2010. Print.