A downlight, also called recessed light, pot light, or can light, is installed into a hollow opening in a ceiling. Light comes out from a hole in the ceiling and concentrates the light in a downward direction appearing as a broad floodlight or a narrow spotlight. It has two parts: the trim and the housing. The trim is the visible part including the thin lining around the edge. The housing is the fixture installed inside the ceiling and has a lamp holder or casing. A casing has a tubular body that encloses the lighting material.

Fire Rated Downlights are installed on ceiling surfaces which are considered to be fire barriers. If the space above the ceiling is occupied by people, either a firehood or a fire rated downlight must be installed.

Local building control authorities determine the amount of time that a ceiling can hold back the fire, thus the term fire-rated ceilings. Typical fire rating for a ceiling is an hour and the best ones can last up to two hours. Cutting a hole in a ceiling to fit downlights will compromise the ceiling’s fire rating. Because downlights are not designed to fit seamlessly into a ceiling, the gaps formed within the light fitting will now be the ceiling’s weakest point where flames and smoke can pour through and spread the fire to the floor above. Ideally, each luminaire in a downlight fitting should be fitted with a fire protection cover which prevents both flames and heat being transmitted through the luminair up into a ceiling gap.

Building regulations for fire safety require a ceiling’s fire integrity to be restored after lighting is fitted. Such regulations indicate that if a fire element is to be effective, then every joint, imperfection or opening to allow services to pass through the element should be adequately protected by sealing or fire-stopping so that the resistance is not impaired.

Upon installation of fire rated downlights, it is best to fit a fire protection cover. However, covers may also be retrofitted quite quickly and economically. Fire protection covers may be woven cloth types or fully intumescent caps. Both can be highly effective in stopping spread of fire, although caps are simpler to install in both new applications and retrofits. Fire protection covers are lightweight making them suitable for plasterboard and suspended ceilings.

Fire rated downlights and accessories are readily available from hardware and electrical retailers or wholesalers. They come in many different colors and designs. Most suppliers emphasize their products’ compliance to current regulations.

The main types of Axial Flow Fans include:

High-Temperature Axial Fans – High-volume fans designed to operate against low flow resistance in industrial convection furnaces. These are found in either single-direction or bi-directional designs. Extremely rugged, they are most often used in high-temperature furnace (up to 1800 degF) applications.

Tube Axial Fans – Cataloged high-volume low-pressure fan line with a wide range of available sizes. Suitable for temperatures up to 250 degF.

Vaneaxial Fans – Axial flow fans with higher pressure capability due to the presence of static vanes.

Variable Pitch Axial fans – Axial fans with manually adjustable blade angles. This allows operation over a much wider range of volume/pressure relationships. The blades are adjusted periodically to optimize efficiency by matching the blade pitch to the varying conditions for the application. (Often used in mining applications).

Variable Pitch on-the-fly Axial Fans – These are similar to “Variable Pitch Axial Fans” except these include an internal mechanism that allows the blade pitch to be adjusted while the fan rotor is in motion. These versatile fans offer high-efficiency operation at many different points of operation.

Variable Speed Fans – All of the fans described above can be used in conjunction with a variable speed driver. This might be an adjustable frequency AC controller, a DC motor and drive, a steam turbine driver, etc. Flow control by means of variable speed is typically smoother and more efficient than by means of damper control. Significant power savings (with reduced cost of operation) are possible if variable speed fan drives are used for applications that require reduced flow operation for a significant portion of the system operating life.

Airfoil Centrifugal Fans are used for a wide range of applications in many industries, hollow-bladed airfoil fans are designed, engineered and tested for use in airstreams where high efficiency and quiet operation are required. They are used extensively for continuous service at ambient and elevated temperatures in forced and induced draft applications in the metals, chemical, power generation, paper, rock products, glass, resource recovery, incineration and other industries throughout the world.

Backward Curved Fans – Efficiencies nearly as high as the airfoil design. However, single-thickness metal blades prevent the possibility of dust particle buildup inside the blade. These fans can be built with long-lasting erosion-resistant liners. The robust design allows high tip-speed operation, and therefore this fan is often used in high-pressure applications. This design frequently offers the best compromise for long life and high efficiency.

Backward Inclined Fans – Simple flat blades, but backwardly inclined to match the velocity pattern of the air passing through the fan wheel, which results in high-efficiency operation. These fans are typically used in high-volume, relatively low-pressure, clean air applications.

Radial Blade Blowers – Flat blades oriented in a radial pattern. These rugged fans offer high pressure capability with average efficiency. They are often fitted with erosion-resistant liners to extend the rotor life. The housing design is compact to minimize the floor space requirement.

Forward-Curved Radial Tip Fans – This rugged design is used in high-volume flow rate applications when the pressure requirement is rather high and erosion resistance is necessary. It offers medium range efficiencies. A common application is the dirty side of a baghouse or precipitator. The design is more compact than airfoil, backward curved or backward inclined fans.

Paddle-Wheel Blowers – This is an open impeller design without shrouds. Although the efficiency is not high, this fan is well suited for applications with extremely high dust loading. It can even be offered with field-replaceable blade liners from ceramic tiles or tungsten-carbide. This fan may also be used in high-temperature applications.

Forward-Curve Fans – This “squirrel cage” impeller generates the highest volume flow rate (for a given tip speed) of all the centrifugal fans. Therefore, it is often the smallest physical package available. It is commonly used in high-temperature furnaces.

Industrial Exhausters – Relatively inexpensive, medium-duty, steeply inclined flat-bladed fan for exhausting gases, conveying chips, etc.

Pre-engineered Fans – are series of fans of varying blade shapes that are usually available in only standard sizes. Because they are pre-engineered these fans may be available with relatively short delivery times. Often, pre-engineered rotors with various blade shapes may be installed into a common housing. These are often available in a wide range of volume and pressure requirements to meet the needs of many applications.

Pressure Blowers – High-pressure, low-volume blowers used in combustion air applications in furnaces or to provide “blow-off” air for clearing and/or drying applications.

Surgeless Blowers – High-pressure, low-volume blowers with a reduced tendency for “surging” even at severely reduced flowrates. This allows extreme turndown (low-flow) without significant pulsation.

Water pipe leaking can cause a lot of problem. They will cause a lot of property damage, especially when gone undetected. Water leaks can rot out the wood floors and your ceilings board, and even worst when it cause electrical shorts which might cause fire hazard.

Pipe Leaking

How to deal with water pipe leaking? In order to tackle the leaking problem effectively, one needs to have basic understand on the above subject, followed by proper planning, identifier the source of leaking and fixing it. Pipe leakage can be anywhere, and randomly, therefore the first step to tackle the problem is to trace out the source of the problem and then taking necessary steps to repair the leaking section.
The first step in discovering the source of the problem is by monitoring the water meter measure. In order to do so, the taps in the house and garden have to be turned off and that all the related equipments like toilets, bathrooms, basins, etc are not in operation. Then take the water meter reading. Wait for about 15~20 minutes and then take another reading. The next step is subtract the start reading from the final reading. Multiply by six to determine the amount of litres of water lost per hour. If a leak is detected, fix it by following the subsequent steps.

It may be the pipe is leaking from the spout when the water is turned off. The vast majority of the time, the problem is a damaged seat, stem, or washer. Turn on the handle to drain residual water that might still be in the pipes. Cover the drain with a cloth or paper towel so you don’t lose any parts. Pop off the faucet caps with a small screwdriver if your faucets have them. Use a screwdriver to remove the screw in each handle. Now pull off the handle; if it won’t budge then take a pipe handle puller and place the side bars of the puller under the handle. Now turn the bar at the top of the puller so that the shaft is inserted into the handle. Tighten the bar and pull the handle. To remove the stem, place slip joint pliers around the packing nut and turn counterclockwise until it is loose. Lift out the stem and put it in a bag. Do the same with the other side.

Take the two stems to the hardware store. Having the stems with you will enable you to properly fit new stem washers and/or valve seats. To install new washers, use a screwdriver to remove the stem screw. Now pry out the old washer and put on a new one. Next, insert the stem screw and tighten. Do the same with the other stem.

When you replace a washer, you always need to replace the valve seat. You will need a seat wrench and Teflon tape. Using the appropriate size end of the seat wrench, insert it into the faucet body and turn counterclockwise. Now apply the Teflon tape counter clockwise onto the new valve seat. Then place the valve seat on the appropriate size end off the seat wrench and insert it into the body, turning clockwise to tighten the screws. Replace the caps. Make sure you always clean up the area where you have been working. Don’t cross-thread any of the nuts or the valve seat when reassembling the pipe. Turn on the main water valve again and double-check your pipes to be sure they aren’t leaking. If the faucet works correctly, pat yourself on the back and enjoy the double benefit you just earned; saving money from doing it yourself and gaining useful knowledge in the process.