You can input the max number of heaters and storage tanks, oversize percentage and more. Metraflex Calculators : Metraflex, which offers thermal, vibration, noise, and seismic solutions for pipes, has a variety of helpful calculators and tools.
They offer the Globe vs. Wafter energy savings calculator to compare savings of using a Globe Silent Check Valve over a Wafer style. Acorn Master Mixing Valve Sizing Calculator: This tool helps you size and select the correct master mixing thermostatic valve based on a variety of project types and parameters. PURE Humidifier Load Calculator: This calculator offers both direct entry and values calculation for both direct steam injection and atmospheric steam.
Aluminium and copper can also, under certain conditions, be harmful to health. Stainless steels contain chromium, which increases corrosion resistance, and other alloy elements, such as nickel and molybdenum. But welding of stainless steel can expose workers to chromium and nickel fumes. Next to steel, aluminium is the most commonly used metal in construction, because the metal and its alloys are light, strong and corrosion-resistant.
Copper is one of the most important metals in engineering, because of its corrosion-resistance and high conductivity for electricity and heat. It is used in energized lines, as roof and wall coating and for piping. When used as a roof coating, copper salts in the rain runoff can be harmful to the immediate environment.
Wallboard, often coated with asphalt or plastic, is used as a protective layer against water and wind and to prevent seepage of moisture through the building elements. Gypsum is crystallized calcium sulphate. Gypsum board consists of a sandwich of gypsum between two layers of cardboard; it is widely used as wall covering, and is fire-resistant.
Dust produced when cutting wallboard can lead to skin allergies or lung damage; carrying oversize or heavy board in awkward postures can cause musculoskeletal problems. Wood is widely used for construction. It is important to use seasoned timber for construction work.
For beams and roof trusses of considerable span, glue-laminated wood units are used. Measures are advisable to control wood dust, which, depending on the species, can cause a variety of ailments including cancer. Under certain conditions, wood dust can also be explosive. A crane is a machine with a boom, primarily designed to raise and lower heavy loads. There are two basic crane types: mobile and stationary. Mobile cranes can be mounted on motor vehicles, boats or railroad cars.
Stationary cranes can be of a tower type or mounted on overhead rails. Most cranes today are power driven, though some still operate manually. Their capacity, depending on the type and size, ranges from a few kilograms to hundreds of tonnes. Cranes are also used for pile driving, dredging, digging, demolition and personnel work platforms. Accidents involving cranes are usually costly and spectacular. Injuries and fatalities involve not only workers, but sometimes innocent bystanders.
Hazards exist in all facets of crane operation, including assembly, dismantling, travel and servicing. Some of the most common hazards involving cranes are:. Safe operation of a crane is the responsibility of all parties involved. Crane manufacturers are responsible for designing and manufacturing cranes that are stable and structurally sound.
Cranes must be rated properly so that there are enough safeguards to prevent accidents caused by overloading and instability. Instruments such as load-limiting devices and angle and boom length indicators aid operators in the safe operation of a crane. Powerline sensory devices have proved to be unreliable.
Every crane should have a reliable, efficient, automatic safe- load indicator. In addition, crane manufacturers must make accommodations in the design that facilitate safe access for servicing and safe operation. Crane owners are responsible for keeping their machines in good condition by ensuring regular inspection and proper maintenance and employing competent operators. Crane owners must be knowledgeable so that they can recommend the best machine for a particular job.
A crane assigned to a project should have the capacity to handle the heaviest load it must carry. The crane should be fully inspected by a competent person before being assigned to a project, and then daily and periodically as suggested by the manufacturer , with a maintenance record kept. Ventilation should be provided to remove or dilute engine exhaust from cranes working in enclosed areas.
Hearing protection, when necessary, should be provided. Site supervisors must plan ahead. With proper planning operating near overhead powerlines can be avoided. When work must be done near high-voltage power lines, clearance requirements should be followed see table 1.
When working near powerlines cannot be avoided, the line should either be de-energized or insulated. Signallers should be used to aid the operator near the limit of approach around powerlines. The ground, including access in and around the site, must have the ability to bear the weight of the crane and the load it is lifting. If possible, the crane operating area should be roped off to prevent injuries from overhead lifting.
A signaller must be used when the operator cannot see the load clearly. The crane operator and the signaller must be trained and competent in hand signals and other aspects of the job. Proper rigging attachments must be supplied so that riggers can secure the load from falling or slipping. The rigging crew must be trained in the attachment and dismantling of loads.
Good communication is vital in safe crane operations. All safety features and warning devices should be in working order and should not be disconnected. The crane must be levelled and be operated according to the crane load chart.
The operator should always use sound craning practices. All loads must be fully secured before they are lifted. Movement with a load must be slow; the boom should never be extended or lowered so that it compromises the stability of the crane.
Cranes should not be operated when visibility is poor or when the wind can cause the operator to lose control of the load. There are numerous written standards or guidelines for recommended manufacturing and operating practices. Some are based on design principles, some on performance. Subjects covered in these standards include methods of testing various safety devices; design, construction and characteristics of the cranes; inspection, testing, maintenance and operation procedures; recommended equipment and control lay-out.
These standards form the basis of government and company health and safety regulations and operator training. An elevator lift is a permanent lifting installation serving two or more defined landing levels, comprising an enclosed space, or car, whose dimensions and means of construction clearly permit the access of people, and which runs between rigid vertical guides.
A second category is the service lift dumb waiter , a permanent lifting installation serving defined levels, but with a car that is too small to transport people. Service lifts transport foods and supplies in hotels and hospitals, books in libraries, mail in office buildings and so on. Generally, the floor area of such a car does not exceed 1 m 2 , its depth 1 m, and its height 1. Elevators are driven directly by an electric motor electric lifts; see figure 1 or indirectly, through the movement of a liquid under pressure generated by a pump driven by an electric motor hydraulic lifts.
Electric lifts are almost exclusively driven by traction machines, geared or gearless, depending on car speed. Hydraulic lifts have become widely used since the s for the transport of goods and passengers, usually for a height not exceeding six floors. Hydraulic oil is used as pressure fluid.
The direct-acting system with a ram supporting and moving the car is the simplest one. Technical Committee of the ISO has drafted standards for: loads and speeds up to 2. Each building should be provided with at least one lift accessible to handicapped people in wheelchairs.
Every industrialized country has a safety code drawn up and kept up to date by a national standards committee. Since this work was started in the s, the various codes have gradually been made more similar, and differences now are generally not fundamental. Large manufacturing firms produce units that comply with the codes. In the s the ILO, in close cooperation with the International Committee for the Reglementation of Lifts CIRA , published a code of practice for the construction and installation of lifts and service lifts and, a few years later, for escalators.
These directives are intended as a guide for countries engaged in the drafting or modification of safety rules. A standardized set of safety rules for electric and hydraulic lifts, service lifts, escalators and passenger conveyors, the object being the elimination of technical barriers to trade among the member countries of the European Community, is also under the purview of the European Committee for Standardization CEN.
Safety rules are aimed at several types of possible accidents with lifts: shearing, crushing, falling, impact, trapping, fire, electric shock, damage to material, accidents due to wear, and accidents due to corrosion.
People to be safeguarded are: users, maintenance and inspection personnel and people outside the hoistway and the machine room. Objects to be safeguarded are: loads in the car, components of the lift installation and the building. Committees drawing up safety rules have to assume that all components are correctly designed, are of sound mechanical and electrical construction, are made of material of adequate strength and suitable quality and are free from defects.
Potential imprudent acts of users have to be taken into account. Shearing is prevented by providing adequate clearances between moving components and between moving and fixed parts. Crushing is prevented by providing sufficient headroom at the top of the hoistway between the roof of the car in its highest position and the top of the shaft and a clear space in the pit where someone can remain safely when the car is in its lowest position.
These spaces are assured by buffers or stops. Protection against falling down the hoistway is obtained by solid landing doors and an automatic cut off that prevents movement of the cab until the doors are fully closed and locked.
Landing doors of the power-operated sliding type are preferred for passenger lifts. Impact is limited by restraining the kinetic energy of closing power-operated doors; trapping of passengers in a stalled car is prevented by providing an emergency unlocking device on the doors and a means for specially trained personnel to open them and extricate the passengers.
Overloading of a car is prevented by a strict ratio between the rated load and the net floor area of the car. Doors are required on all the cars passenger lifts to keep passengers from being trapped in the space between the car sill and the hoistway or the landing doors.
Car sills must be fitted with a toe guard of a height of not less than 0. Cars have to be provided with safety gear capable of stopping and holding a fully loaded car in the event of overspeed or failure of the suspension. The gear is operated by an overspeed governor driven by the car by means of a rope see figure 1. As passengers stand upright and move in a vertical direction, the retardation during the operation of the safety device should lie between 0.
Depending on national legislation, lifts intended mainly for the transport of goods, vehicles and motor cars accompanied by authorized and instructed users may have one or two opposite car entrances not provided with car doors, under the condition that the rated speed does not exceed 0. On heavy-duty freight elevators goods lifts , the landing doors are usually vertical bi-parting power-operated doors, which usually do not meet these conditions.
In such a case, the required car door is a vertically sliding mesh gate. The clear width of the lift car and the landing doors must be the same to avoid damage to panels on the lift car by fork trucks or other vehicles entering or leaving the lift.
The whole design of such a lift has to take account of the load, the weight of the handling equipment and the heavy forces involved in running, stopping and reversing these vehicles. The lift car guides require special reinforcement. When the transport of people is permitted, the number allowed should correspond to the maximum available area of the car floor. For example, the car floor area of a lift for a rated load of 2, kg should be 5 m 2 , corresponding to 33 persons.
Loading and accompanying a load must be done with great care. Figure 3 shows a faulty situation. All modern lifts are push-button and computer controlled, the car switch system operated by an attendant having been abandoned.
Single lifts and those grouped in two- to eight-car arrangements are usually equipped with collective controls which are interconnected in the case of multiple installations. The main feature of collective controls is that calls can be given at any moment, whether the car is moving or standstill and whether the landing doors are open or closed.
Landing and car calls are collected and stored until answered. Regardless of the sequence in which they are received, calls are answered in the order that most efficiently operates the system.
A technical dossier should be submitted to the inspector by the manufacturers. The elements to be examined and tested and the way the tests should be run are listed in the safety code.
Specific tests by an approved laboratory are required for: locking devices, landing doors possibly including fire tests , safety gear, overspeed governors and oil buffers. Certificates of the corresponding components used in the installation should be included in the register. After a lift is put into service, periodic safety examinations should be conducted, with the intervals depending on traffic volume.
These tests are intended to ensure compliance with the code and the proper operation of all safety devices. Components that do not function in normal service, such as the safety gear and buffers, should be tested with a car empty and at reduced speed to prevent excessive wear and stresses that can impair the safety of a lift. A lift and its components should be inspected and maintained in good and safe working order at regular intervals by competent technicians who have obtained skill and a thorough knowledge of the mechanical and electrical details of the lift and the safety rules under the guidance of a qualified instructor.
Preferably the technician is employed by the supplier or erector of the lift. Normally a technician is responsible for a specific number of lifts.
Maintenance involves routine servicing such as adjustment and cleaning, lubrication of moving parts, preventive servicing to anticipate possible problems, emergency visits in the case of breakdowns and major repairs, which are usually done after consultation with a supervisor. The overriding safety hazard, however, is fire. Because of the risk that a lit cigarette or other burning object might fall into the crack between the car sill and the hoistway and ignite lubricating grease in the hoistway or debris at the bottom, the hoistway should regularly be cleaned out.
All systems should be at zero energy level before maintenance work is begun. In single-unit buildings, before any work is started, notices should be posted at each landing indicating that the lift is out of service. For preventive maintenance, careful visual inspection and checks of free movement, the condition of contacts and proper operation of the equipment are generally sufficient.
The hoistway equipment is inspected from the top of the car. An inspection control is provided on the car roof comprising: a bi-stable switch to bring it into operation and to neutralize the normal control, including the operation of power-operated doors.
Up and down constant pressure buttons allow movement of the car at reduced speed not exceeding 0. The inspection operation must remain dependent on the safety devices closed and locked doors and so on and it should not be possible to overrun the limits of normal travel. A stop switch on the inspection control station prevents unexpected movement of the car. The safest direction of travel is down. The technician must be in a safe position to observe the work environment when moving the car and possess the appropriate inspection devices.
The technician must have a firm hold when the car is in motion. Before leaving, the technician must report to the person in charge of the lift. An escalator is a continuous moving, inclined stairway which conveys passengers upward and downward. Escalators are used in commercial buildings, department stores and railway and underground stations, to guide a stream of people in a confined route from one level to another. Escalators consist of a continuous chain of steps moved by a motor-driven machine by means of two roller chains, one at each side.
The steps are guided by rollers on tracks which keep the step treads horizontal in the usable area. At the entrance and exit, guides ensure that over a distance of 0. Step dimensions and construction are shown in figure 4. On the top of each balustrade, a handrail should be provided at a height of 0.
The handrail at each extremity of the escalator, where the steps move horizontally, should extend at least 0. The handrail should enter the newel at a low point above the floor, and a guard should be installed with a safety switch to stop the escalator if fingers or hands are trapped at this point.
Other risks of injury to users are formed by the clearances necessary between the side of the steps and the balustrades, between steps and combs and between treads and step risers, the latter more particularly in the upward direction at the curvature where a relative movement between consecutive steps occurs.
The cleating and smoothness of the risers should prevent this risk. Figure 4. Escalator step unit 1 X : Height to next step not greater than 0. People may ride with their shoes sliding against the balustrade, which can cause trapping at the points where the steps straighten out. Clearly legible signs and notices, preferably pictographs, should warn and instruct users. A sign should instruct adults to hold the hands of children, who may not be able to reach the handrail, and that children should stand at all times.
Both ends of an escalator should be barricaded when it is out of service. Machine rooms and driving and return stations should be easily accessible to specially-trained maintenance and inspection personnel only. These spaces can lie inside the truss or be separate. The clear height should be 1. The clear height above the steps at all points should be not less than 2. The starting, stopping or reversal of movement of an escalator should be effected by authorized people only.
If the country code permits operating a system that starts automatically when a passenger moves past an electric sensor, the escalator should be in operation before the user reaches the comb. Escalators should be equipped with an inspection control system for operation during maintenance and inspection. Maintenance and inspection along the lines described above for lifts are usually required by authorities. A technical dossier should be available listing the main calculation data of the supporting structure, steps, step driving components, general data, layout drawings, schematic wiring diagrams and instructions.
Before an escalator is put into service, it should be examined by a person or organization approved by the public authorities; subsequently periodic inspections at given intervals are needed.
A passenger conveyor, or power-driven continuous moving walkway, may be used for the conveyance of passengers between two points at the same or at different levels.
Passenger conveyors are used to transport a great number of people in airports from the main station to the gates and back and in department stores and supermarkets. When the conveyors are horizontal, baby carriages, pushcarts and wheelchairs, luggage and food trolleys can be carried without risk, but on inclined conveyors these vehicles, if rather heavy, should be used only if they lock into place automatically.
The ramp consists of metal pallets, similar to the step treads of escalators but longer, or rubber belt. The pallets must be grooved in the direction of travel, and combs should be placed at each end. The pallets and belt should move horizontally over a distance of not less than 0. The walkway runs between balustrades that are topped with a moving handrail that travels at substantially the same speed.
The speed should not exceed 0. The safety requirements for passenger conveyors are generally similar to those for escalators and should be included in the same code.
Building hoists are temporary installations used on construction sites for the transport of persons and materials. Each hoist is a guided car and should be operated by an attendant inside the car. In recent years, rack and pinion design has enabled the use of building hoists for efficient movement along radio towers or very tall smoke stacks for servicing.
No one should ride a material hoist, except for inspection or maintenance. The standards of safety vary considerably. In a few cases, these hoists are installed with the same standard of safety as permanent goods and passenger lifts in buildings, except that the hoistway is enclosed by strong wire mesh instead of solid materials to reduce the wind load.
Strict regulations are needed although they need not be as strict as for passenger lifts; many countries have special regulations for these building hoists. However, in many cases the standard of safety is low, the construction poor, the hoists driven by a diesel engine winch and the car suspended by only a single steel wire rope. A building hoist should be driven by electric motors to ensure that the speed is kept within safe limits.
The car should be enclosed and be provided with car entrance protections. Hoistway openings at the landings should be fitted with doors that are solid up to a height of 1 m from the floor, the upper part in wire mesh of maximum 10 x 10 mm aperture. Sills of landing doors and cars should have suitable toe guards. Cars should be provided with safety gear. One common type of accident results when workers travel on a platform hoist designed only for carrying goods, which do not have side walls or gates to keep the workers from striking a part of the scaffolding or from falling off the platform during the journey.
A belt lift consists of steps on a moving vertical belt. Accordingly, such a lift should be used only by specially trained personnel employed by the building owner or a designee. Generally, the hoistway for any lift extends over the full height of a building and interconnects the floors. A fire or the smoke from a fire breaking out in the lower part of a building may spread up the hoistway to other floors and, under certain circumstances, the well or hoistway may intensify a fire because of a chimney effect.
The hoistway should be totally enclosed by solid walls of non-combustible material that would not give off harmful fumes in case of a fire. A vent should be provided at the top of the lift hoistway or in the machine room above it to allow smoke to escape to open air. Like the hoistway, the entrance doors should be fire resistant. Requirements are usually laid down in national building regulations and vary according to countries and conditions.
Landing doors cannot be made smokeproof if they are to operate reliably. No matter how tall the building, passengers should not use lifts in case of fire, because of the risks of the lift stopping at a floor in the fire zone and of passengers being trapped in the car in the event of failure of the electrical supply.
In general, one lift that serves all floors is designated as a lift for firefighters that can be put at their disposal by means of a switch or special key on the main floor. When firefighters use lifts, the normal operational controls are overridden. The construction, maintenance and refinishing of elevator interiors, installation of carpeting and cleaning of the elevator inside or out may involve the use of volatile organic solvents, mastics or glues, which can present a risk to the central nervous system, as well as a fire hazard.
Although these materials are used on other metal surfaces, including staircases and doors, the hazard is severe with elevators because of their small space, in which vapour concentrations can become excessive. The use of solvents on the outside of an elevator car can also be risky, again because of limited air flow, particularly in a blind hoistway, where venting may be impeded. A blind hoistway is one without an exit door, usually extending for several floors between two destinations; where a group of elevators serves floors 20 and above, a blind hoistway would extend between floors 1 and While lifts and hoists involve hazards, their use can also help reduce fatigue or serious muscle injury due to manual handling, and they can reduce labour costs, especially in building construction work in some developing countries.
On some such sites where no lifts are used, workers have to carry heavy loads of bricks and other building materials up inclined runways numerous floors high in hot, humid weather. Cement is a hydraulic bonding agent used in building construction and civil engineering. It is a fine powder obtained by grinding the clinker of a clay and limestone mixture calcined at high temperatures.
When water is added to cement it becomes a slurry that gradually hardens to a stone-like consistency. It can be mixed with sand and gravel coarse aggregates to form mortar and concrete. There are two types of cement: natural and artificial. The natural cements are obtained from natural materials having a cement-like structure and require only calcining and grinding to yield hydraulic cement powder.
Artificial cements are available in large and increasing numbers. The net-present or net-future values from a LCCA will ensure the total costs associated with a particular equipment selection have been considered. Comparing alternative LCCAs for different potential equipment pieces is fast and routine, but the output is very telling. Once a conclusion is reached on a particular equipment selection, document a summary of the evaluation, the peer contenders, and three reasons the selected equipment was chosen.
In circumstances where others will be procuring, if options between equipment choices will still be made, it is important to rank two to five of the highest evaluated equipment, with short comments why. The key aspects that mechanical engineers need to consider in equipment selection are nuanced.
It can be as simple or complex as necessary, but regardless, it must be comprehensive. It requires an engineer to communicate efficiently and reinforce conclusions, and should result in ongoing collaboration with the owner to ensure desired attributes are captured.
Both the right and left brain will be activated to achieve both the art and science of evaluating abstract conditions and technical applications.
It requires financial sensitivity and analysis. Most of all, a good foundation in engineering is needed, along with common sense and the ability to understand how important these nuanced selections are to achieve many years of comfort, safety, and performance.
Seth Pearce is director of design and development for Southland Energy, a division of Southland Industries. Heating and Ventilation 14 aspects to consider in equipment selection Mechanical engineers should consider these key aspects when specifying systems for a building owner.
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Grafting wax. A watering can or watering pot is a portable container, usually with a handle and a funnel, used to water plants by hand. It has been in use since at least 79 A. Apart from watering plants, it has varied uses , as it is a fairly versatile tool. What are the tools and simple equipment needed in nursery operation? Category: home and garden landscaping. Furrow opener: It is used for opening narrow and shallow furrow after sowing seeds in nursery.
Hand leveler: It consists of narrow rectangular metal blade attached to long wooden handle Plate Trowel Khurpi : It is of shovel shape but small in size with iron blade and wooden handle. What are the types of nursery? What are traditional tools? What are farming tools? What tools do we need for gardening? What are the basic gardening tools? Shovel and spade. How much does it cost to start a plant nursery?
What is nursery and its importance? What are the classification of hand tools? What is the mean of equipment? What are the gardening tools and their uses? To make your research easy, we've rounded up the most common gardening tools and their uses:. Garden Gloves. What is farm tools and their uses? What are the tools used in gardening?
What Every gardener needs?
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