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Understanding Shingle Roofs

Posted January 29, 2007 by Michael
Categories: ASHI Home Inspection, ASHI Home Inspector, Certified Home Inspection, Certified Home Inspector, Florida Home Inspector, Home Inspection, Home Inspection Florida, Home Inspection Tampa, Home Inspector, Home Inspector Florida, Home Inspector Tampa, Licensed Home Inspector, Tampa Home Inspector

What are Asphalt Roof Shingles?

Asphalt roof shingles are the most common covering found while inspecting roofs in Florida. Early shingles were made by saturating rag-felts with asphalt and by coating each side of the saturated felt with an asphalt-mineral filler-coat, covering the top surface of the shingle with mineral granules (sunlight and weather resistance) and coating the bottom surface with a material to prevent shingles from sticking together in storage or shipment. Beginning in the 1940’s the felt mat was changed to a zero rag-content using wood fibers and cellulose (newspaper). More recently many manufacturers began producing shingles using a fiberglass mat to replace the felt. The fiberglass mat was thought to have good tear resistance, possibly slightly better fire resistance, and as the mat was generally thinner than the felt mat, we believe that there were also economic advantages for both the manufacturer (less asphalt used in the mat) and the roofing installer (lighter material, easier to install).

Ten Reasons Roofs Fail

1. Blisters. Bubble-like or long, thin raised areas on the roof are called blisters. Blisters are the most common roofing problem. They occur when a gas, usually water vapor, is trapped within the roofing system either between the plies or between the plies and the insulation. The heat of the sun during the day causes the gas to expand. The expansion of the gas creates a pressure within the system that pushes the plies apart, resulting in the blister.

Blisters would not occur if there were not some reason for moisture in the membrane. Two common ones are applying the roof to a damp substrate, as during a re-cover, and applying wet materials, such as felts, that have absorbed dew or rain on the edges. The moisture that causes blisters can often be traced back to another problem: improper storage of insulation, which allows water to soak through holes in shrink wrap or at the bottom of the stack where shrink wrap doesn’t cover. Moisture can also get into a roof installed in the presence of rain, snow or dew.

2. Open laps. Open laps in the field membrane, but especially in the flashings, are another problem. Open laps are just carelessness on the part of the installer. Usually it means that the installer has failed to apply adhesive to the entire lap. Sometimes it is caused in built-up and modified-bitumen systems when the bitumen is applied too cold. The laps appear to be closed, but open up as the roof ages.

In single-ply membranes, open laps are usually caused by improper surface preparation, such as adhering to a dirty membrane, heat welding at too cold of a temperature, not allowing the adhesive to dry properly or applying too much or too little adhesive.

3. Splitting. The most common splits occur when a metal accessory is flashed with a membrane material. As the temperature changes, metals and membranes expand and contract at very different rates. Because the membrane generally cannot move as much as the metal, it will eventually fatigue and crack when it is adhered to metal. This problem is not as common with single-ply membranes with better expansion and contraction capabilities, but it is common in asphalt and coal tar systems.

Splits occur frequently in expansion joints. Contractors rarely know how to properly terminate an expansion joint cover. They run it to the wall and stop it dead. Unfortunately, the movement in the building does not stop at the end of the expansion joint and, consequently, it rips open any attempt to seal that edge. Splits are also common at joints within the expansion joint cover itself.

Splits are not limited to flashings, however. As most roofs age, they become more brittle and less resilient. This means that they become less resistant to movement from common sources such as temperature changes, foot traffic and substrate movement. Because the roof cannot flex or stretch as well as it did when new, it cracks.

Probable Cause:

It’s possible that shingles made by some manufacturers do not meet the ASTM Standards for tear resistance.

Even where shingles meet the Standards, it’s possible that the standards themselves were defective.

In any case, Fiberglass mat may lack adequate tear resistance.

Self-sealing tabs on shingle backs may glue shingles together with too much strength, causing the roof covering to form a single large membrane which cannot accommodate large temperature changes.

Reduced total amount of asphalt in thin fiberglass mats might become brittle after exposure to heat and sunlight.

Temperature swings probably contribute to the onset and extent of tearing, and we’d expect worse tearing where temperature swings are more extreme such as in Northern climates.

Nailing or placement pattern of shingles: “laddering” vs. “staggered.” On laminate and strip type shingles we have inspected roofs on which damage is found occurring at the corners of shingles rather than in the middle of the shingle material. It appears that as temperatures dropped and the glued-together-roof-membrane cools and contracts, the natural point at which movement occurs is where shingles are end-butted together. When the pattern of end-butts is laddered rather than staggered up the roof we have found corners tearing off of shingles following the laddering pattern exactly. (Laddering is not a recommended installation pattern according to NRCA and ARMA publications nor according to instructions from some manufacturers.) Laddering alone cannot be blamed for this failure however, as we have seen similar shingle tearing following a staggered end-butt pattern up other roofs. However laddering may indeed create a more localized natural point of separation on a roof, causing most of the movement to occur in a smaller area when the roof material contracts with cooling.

4. Punctures. The most preventable failure symptom, punctures usually occur because of carelessness on the part of people visiting the roof: HVAC technicians, window washers, painters, maintenance staff, smokers and tenants. Punctures can also occur because of debris left, blown or tossed on the roof. They may appear as tears or holes.

5. Penetrations. Another common failure location is penetrations. Of particular concern are pitch pans. There are three failures common to pitch pans: the sealer itself, the container in which it sits and the penetration to which the sealant is supposed to adhere. Almost all sealers used in pitch pans will crack eventually due to loss of plasticizer or aging. If the penetration is not stabilized, vibration or movement of the penetration can cause the sealant to crack around the penetration. If a penetration is not thoroughly cleaned of asphalt before installing pourable sealers, the sealer will not adhere to the penetration.

Other types of penetration flashings also can fail. Concrete curbs filled with sealer will crack if not fully supported underneath. Metal pans eventually rust and lose adhesion to the sealer. Rubber and plastic boots will deteriorate with ultraviolet radiation exposure. The sealant used at metal penetration flashings eventually deteriorates with exposure and may not seal to the penetration if the penetration has not been properly cleaned before installation. The penetration flashing may also leak if the wrong diameter flashing is used or the cover is not correctly installed.

6. Wrinkles. Wrinkles can occur both in the flashings and within the membrane itself. When there is differential movement between the roof deck and the perimeter, the flashings will wrinkle on a 45-degree angle. When a wrinkle reaches the edge of a membrane or flashing, the opening left at the end of the wrinkle is called a fishmouth because of its bass-mouth-like appearance. Depending on the ply in which the wrinkle occurred, the fishmouth can be a tunnel for water to get down into the building.

Wrinkles within the membrane will eventually fatigue and crack. Because they are raised above the surface of the roof, they are more prone to traffic damage, scuffing and surfacing loss than the rest of the roof.

7. Flashings. Flashings must be fastened at the top to prevent the membrane from slipping down the wall or curb, or to keep the membrane from creating a funnel into the building. A flashing normally terminates under a metal counter flashing. If it does, the counter flashing can create problems if the top is not properly sealed or the sealant has failed. If the metal counter flashing does not lap the membrane enough, it may fail to divert water from the flashing and instead funnel water into it.

8. Surfacings. Surfacings on membranes may provide protection from ultraviolet radiation and damage from traffic on the roof. They also may be a component of the fire rating of the roof. In the case of ballasted roofs, surfacings may be the only thing keeping the roof in place other than gravity. When the surfacing gets displaced or worn off, either from foot traffic, repair persons, wind, etc., this protection no longer applies.

9. Fasteners. In mechanically attached roofing systems, movement from wind will cause fasteners to rock back and forth with the gusts. Eventually, this movement causes the hole in the deck around the fastener to enlarge and the fastener to back out. The fastener heads can eventually puncture the membrane from below. But fastener back-out is not limited to single-ply membranes. It is also a common occurrence in metal roofing and in metal accessories on membrane roofs. In these cases, the backed-out fasteners leave holes where water can directly enter the building. This is an especially serious problem when a coping — the metal cap on the top of a parapet — is fastened through the top of the horizontal portion and not through the vertical flanges.

10. Abuse and Neglect. When it comes to mistreating a roof, the most common culprits are air conditioning and maintenance technicians, window washers, and sign installers. It is not unusual to see debris — ranging from screws and bits of sheet metal all the way up to empty refrigerant canisters and abandoned HVAC units — left on roofs after an air conditioning repair visit.

Small debris can cut into the roof if the debris is stepped on; large debris will work its way into the roof membrane during the hot months of the year. Sign installers routinely install conduit through the walls without properly sealing the penetrations. The water that gets into those penetrations works its way through the walls and into the building, disguised as a roof leak. Window washers and painters hang access equipment over the side of the roof, kick flashings and damage parapets, allowing leaks to occur. All of these groups of people can wreak havoc on base flashings, which get kicked, punctured with tools and machinery, and have mechanical equipment run up against them.

Owners contribute to the early demise of their own roofs by not properly maintaining them and failing to repair small problems, before they become big ones.

Special Defects in Roofing Materials

Splice shingles used to keep material moving during the manufacturing process should be discarded but they almost always end up installed on the roof.

Blisters in shingles wear off from weather or foot traffic, becoming pits, causing moisture absorption.

Aesthetic or Cosmetic Roofing Issues

Some consumers have concerns with how their shingles look on the roof as much as with how long the roof will last. Roofing manufacturers offer a wide variety of products which give different “looks” and shadings. It’s possible that in addition to site and installation conditions, variations in manufacturing process (granule adhesion, bleed-through) can affect how the roof looks from the ground. We’ve also investigated client concerns with shadows appearing in early morning or late afternoon which show variations in the roof surface. (Some shadows which are only of cosmetic nature may be caused by slight buckling or unevenness in the roof decking and may not indicate a structural or durability concern.)

If you have particular concerns about roof appearance ask your roofer if s/he can direct you to a house where the product which interests you is already installed. Remember that site differences (orientation to sun, shade trees, height above ground, roof pitch, and probably other factors) may make shingles look a bit different on your house.

Roofing Warranties - Valuable or Worthless?

In certain instances specific roofing products have shown common early failure, failing in a characteristic pattern which is easily identified (such as the thermal splitting defect. Some manufacturers offer limited warranty coverage of their product. Many roofers also guarantee their work to be free from leaks, but usually for a time period substantially shorter than the manufacturer’s rated life of the roof material.

In cases which we’ve handled recently involving thermal splitting or tearing of fiberglass-based asphalt shingles, some manufacturers (such as GAF) offer a limited product warranty. Following a fairly involved claims procedure requiring documentation, photographs, and a sample of damaged material the manufacturer may elect to warrant the roofing material on a pro-rated basis depending on the age of the roof and its warranted life. Sometimes the manufacturer’s warranty covers only material cost, not installation cost (labor, demolition, removal of old materials) unless the roofing contractor chooses to extend such coverage.

The cost of roofing material is not the main ingredient in roofing cost. Labor and possibly disposal of old roofing material are significant costs. Out of concern for future roof life, some roofers are reluctant to install new roofing atop failed material even where additional layers of roofing are permitted by local codes.

Some homeowners are reluctant to install as new roofing the same product which failed early in the first place. Manufacturers might have changed the formulation of the product to improve durability, but they are understandably reluctant to say so, out of concern for increasing product liability. Without assurance from the manufacturer that a product which failed early has been modified to correct the problem, we advise our clients to consider using alternative products with design and performance expectations having a better track record.

Staying Out of Trouble

Preventing problems begins with the design of the roof and choice of materials. The roof membrane chosen should reflect the characteristics of the building. For instance, if there will be a lot of foot traffic, the facility executive should plan on using a system that will be resistant to such damage. If the roof is wide open and there will be a great deal of thermal movement in the structure, a stretchable material such as an EPDM membrane is a better choice than a system that has limited elongation capabilities.

Details must be carefully thought out prior to installation. For example, a transition from a gravel stop to a parapet is a poor building design that must be compensated for in the roof design. A metal transition piece can help alleviate problems that occur as a result of differential movement and different directional movement between the gravel-stop portion and the parapet portion. Correcting slope-to-drain problems should be determined at the design stage.

Second, the roof must be properly installed. This means using dry materials and installing them according to the design details or manufacturer’s requirements. Expansion joints have to terminate in a way that the end of the joint will still compensate for building movement. This means that there should be no material crossing the joint — not gravel stops, not copings, not membrane and certainly not roofing cement — that cannot flex or move with the movement of the structure. Seams should be adhered.

Finally, the roof must be maintained. Roof access should be limited to only those who need to be there. Keep smokers, lunches and sunbathers off the roof. Not only will the cigarettes burn holes in the membrane, the foot traffic will damage the surface and cause the roof to fail prematurely. Owners should monitor the activity of sign installers and window washers to be sure that they are not damaging the roof as they work. New HVAC installations should be flashed not by the mechanical contractor but by a competent roofing contractor to be sure that the penetrations are sealed.

The roof itself should be examined twice a year and drains cleared and roof debris removed. All small problems like punctures and sealant failures should be addressed at this time to be sure that they are not causing problems that will lead to failure. A roof’s life is finite, but it doesn’t have to be short lived. Some common sense when designing the roof, some attention to detail when installing it, and some care when using it will maximize its life.

Tampa Home Inspector

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Quick Answers to Plumbing Questions

Posted January 27, 2007 by Michael
Categories: ASHI Home Inspection, ASHI Home Inspector, Certified Home Inspection, Certified Home Inspector, Florida Home Inspector, Home Inspection, Home Inspection Florida, Home Inspection Tampa, Home Inspector, Home Inspector Florida, Home Inspector Tampa, Licensed Home Inspector, Tampa Home Inspector

Q - Sometimes when when I flush the toilet it keeps running until I jiggle the handle. What should I do?

A - It sounds as if the toilet flush handle gets stuck, causing the tank stopper to stay open. This allows the water in the tank to continuously flow into the bowl. Make an adjustment by oiling, tightening. or replacing the flush handle.

Q - The hot water pipe to my kitchen sink is leaking. How do I make a quick repair?

A - To temporarily stop a small leak, break off a pencil point in the pipe hole and then wrap the pipe with three layers of plastic electrician’s tape, extending 3 inches on either side of the hole. You can also clamp a piece of rubber, such as an old rubber glove, over the leak. If it’s a major leak, though, turn off the water supply immediately at the main shutoff valve and replace the pipe.

Q - When my washing machine shuts off abruptly, the water supply pipes make a loud banging noise. Is there anything I can do to stop this?

A - Water hammer (the noise you’ve described) occurs because the water in the pipes slams to a stop, causing a shock wave and a hammering noise. It’s not only annoying but also destructive to the pipes. You can minimize or eliminate water hammer by installing air chambers dead-end pieces of pipe. Most washing machine manufacturers recommend extra-long chambers—up to 24 inches—to provide added cushion for abrupt turnoffs.

Q - I have an old brass faucet in my bathroom that I want to keep, but it constantly drips hot water from its spout. I’ve replaced the washer in the hot water faucet, but the spout still drips. How can I repair the faucet so it stops wasting my hot water?

A - A spout leak in a compression faucet like yours is caused either by a defective seat washer or a damaged valve seat. You can replace most valve seats with exact duplicates, using a valve seat wrench. If a worn valve seat can’t be removed, use a valve seat dresser to grind it until smooth.

Q - Should we use plastic or copper pipe to install a new water softener in our system?

A - First check your local plumbing code on plastic pipe. Some areas don’t allow it at all, and others allow it for everything but drinking water supply pipes. If permitted, plastic piping can be a good choice, because it’s less expensive. easier to work with (to cut, join, and maneuver), self-insulating, and resistant to weather and corrosion.

Q - What causes our water heater to make loud rumbling noises?

A - The two most common causes for such noises are steam and sediment in the tank. You can often correct steam problems by merely lowering the thermostat setting. If you suspect a faulty thermostat, turn the setting all the way down: then if the heat source doesn’t go off, replace the thermostat. To get rid of problem-causing sediment in your water heater, open the drain valve at the bottom of the tank and drain off a little water until it runs clear. Draining the sediment should eliminate noise problems and allow your heater to operate more efficiently.

Q - We always have a soap ring in our bathroom sink because the pop-up stopper doesn’t open far enough for the water to drain out quickly. How do I adjust it?

A - If the stopper is so tight that the sink doesn’t drain properly, you’ll need to get under the sink to reset the pivot rod by squeezing the spring clip and inserting the rod in the next higher hole. Also remove the pop-up stopper and clean it periodically. Hair and debris can cause sluggish drainage.

Q - I need to cut a new piece of copper pipe for the supply run to my sink. What are the best tools and techniques to use?

A - It’s best to use a pipe cutter with a specially designed blade for copper pipe. You can also use a fine-toothed hacksaw, but making a straight cut with it is more difficult. After you’ve cut the pipe, clean off any burrs (inside or out) with a half-round file.

Q - Our friends have an instant hot water dispenser mounted on their kitchen sink. They say it conserves energy because it eliminates the need to boil water for tea, instant coffee, soup, and the like. Can I install one of these hot water dispensers myself?

A - You can do the plumbing and installation of most hot water dispensers in an afternoon, but unless you’re familiar with wiring techniques, leave the electrical hookup to a professional. The project involves attaching the dispenser faucet onto the sink rim or countertop,tapping into the cold water pipe with a saddle tee fitting, and mounting the hot water holding tank under the sink. By the way, your friends are right about the dispenser being an energy-saver.

Q - I don’t really understand what makes a plumbing system work. The purposes of pipes to supply water and to drain waste seem clear enough, but what’s the purpose of vent pipes?

A - Plumbing works because of constant water pressure (about 50 pounds per square inch) in hot and cold supply pipes, the pull of gravity in drainpipes, and the balance of air pressure in vent pipes. Each fixture needs a vent to get rid of sewer gas and prevent a buildup of pressure in the pipes.

Q - We want to add a second sink in the master bathroom. Can we extend the pipes that are already there?

A - Yes, you can. You’ll need to tap into the existing supply, drain, and vent pipes, run new piping to the desired location, and hook up the new fixture.

Q - I’ve tried using a plunger and chemical drain cleaners, but my tub is still clogged. What else can I do before I resort to calling a plumber?

A - When working with water that contains chemical cleaners, use rubber gloves, bail out any standing water. don’t plunge, and avoid splashing. For a stubborn clog, use a snake. Feed the snake down the drain or overflow pipe to the trap to break up the blockage. If that doesn’t work. the problem is probably deep down in the main drain.

Q - Can you give me some advice before I replace a worn-out toilet with a new one?

A - Since a toilet is a major water guzzler in a home, choose one that conserves water. Buy a toilet that’s ready to install, with flush assembly in place. Most important, carefully measure the roughing-in distance and select a new toilet that will fit properly in the space. Actual installation takes a little muscle (lifting the old and new toilet off and on) and some time, but doing the job yourself can save you the high cost of a plumber.

Q - When the weather gets hot and humid, our toilet tank sweats so much that the floor tiles below the tank are starting to loosen. What can I do to prevent toilet tank condensation?

A - Before treating a sweating tank problem. be sure that a leak is not the culprit. To stop condensation on the tank, install a foam jacket (sold inhardware stores) or pieces of ‘12inch-thick foam rubber inside the tank. You’ll need to empty the water from the tank before you glue the foam in place. Another solution—though moreexpensive and involved—is to install a tempering valve.

Q - The trap under my kitchen sink has corroded through and started to leak. I’d like to replace it but don’t know where to start

A - The hardest part of replacing a trap is loosening the couplings that are sometimes frozen in place on the old trap. Start by emptying the trap through the cleanout plug (if it has one) into a pail. Use a tape-wrapped wrench and counterclockwise force to remove the couplings at the tailpiece and drainpipe. Before installing a new trap, coat the threads of the connecting pipes with pipe joint compound or pipe-wrap tape to guard against leaks.

Q - The water doesn’t drain out of our dishwasher. Any suggestions before I call for repair?

A - There are three common causes for standing water in the bottom of a dishwasher: a plugged strainer basket in the tub of the dishwasher, a dirty air gap. or a dirty hose loop that vents the appliance. Each is easily remedied—just clean out dirt, grease, or food buildup.

Tampa Home Inspector

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Electric Current & Resistance

Electric Current Flow

Electric current flow can be defined as the flow of electrons through a conductor (wire) or circuit. This passage of electrons is often described as being analogous to the flow of water in a pipe or hose. For example, water flows through a pipe or hose because it is under pressure. Similarly, electric current surges through a wire because it is under pressure. Earlier, voltage was defined as the pressure, or moving (electromotive) force, that causes current (electrons) to flow in an electrical circuit. Furthermore, just as the size of a hose or pipe can affect the degree of water pressure, the size of an electrical wire can affect the flow of current passing through it. The maximum current-carrying capacity of a particular-size wire is called its ampacity.

As electric current passes through your electrical system, it reaches your receptacles and switches where, again like water, it becomes available for use, provided that you flip the switch on your wall or appliance just as you would turn the faucet on at your sink. And, like the water, once the electric current is used, it exits the system. Instead of exiting through a drainpipe, the current exits (or returns to the utility) by means of a grounded conductor.

Flow Resistance

The passage of electric current through a wire is not only restricted by the size of the wire and the amount of voltage pressure but also by the material of which it is made. Some materials resist the flow of electricity more than others because of their chemical composition. Imagine water trying to flow along an incline; if the incline is downward, the flow will be unrestricted; if the incline is upward, the flow will be resisted. Whether the incline is sharp or shallow will affect the speed of the water flow, and if the pressure is not sufficient or the upward incline is too great, then the flow may be stopped altogether. Further, if the incline is strewn with obstacles, like the bed of a stream is strewn with boulders and stones, then the flow will be slowed in comparison with that on a smooth incline. It is the chemical composition of a given material that determines whether it is “rock strewn” or “smooth.”

Materials that allow electric current to pass through them fairly easily are electrical conductors, while materials that prevent the passage of electric current are insulators. Common conductors include copper and aluminum, which are used in the manufacture of electrical wiring. Most metals are good electrical conductors, yet even these offer some resistance to the flow of electric current. This property can be measured in units of resistance called ohms. Materials commonly used as insulators include glass, various plastics, and rubber.

Tampa Home Inspector

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After a Water Damage Event

Posted January 24, 2007 by Michael
Categories: ASHI Home Inspection, ASHI Home Inspector, Certified Home Inspection, Certified Home Inspector, Florida Home Inspector, Home Inspection, Home Inspection Florida, Home Inspection Tampa, Home Inspector, Home Inspector Florida, Home Inspector Tampa, Licensed Home Inspector, Tampa Home Inspector

Pipes break. Toilets overflow. Water heaters fail abruptly. Natural disasters, like windstorms, floods and earthquakes, as well as hurricanes, tornadoes or fire, can occur with little or no warning. When a major or catastrophic water damage event occurs it’s important to respond as quickly as possible.

Immediate Action Is important

By taking immediate action you will:

Reduce the amount of damage and loss of personal belongings and household goods;
Mitigate the amount of rust, rot, mold and mildew that may develop;
Lower the likelihood that the water will lead to structural problems;
Increase your chances of salvaging usable materials from the site.

After a Water Damage Event

Your first priority after a water damage event is to protect the occupants of your home. Take all appropriate precautions that are directed by your local emergency management officials. Then, address the issue of protecting your home and belongings.

After the threat of physical danger has passed you should begin immediately to assess the damage and take the following steps:

Ensure that its safe to venture out of the home. If you’ve been evacuated to a shelter, be sure it is safe to return home.
Ensure that it is safe to use electrical power. Water and electricity are a dangerous combination.
Ensure that the natural gas sources are safely secured.
Make sure the home is structurally safe to enter or reoccupy.
Secure the building exterior to prevent further moisture intrusion. This can include hoarding up broken windows, making temporary roof repairs, sealing cracks or tacking down plastic sheeting against open gaps in walls or roofs.

After Major Water Damage Event

Disconnect all electronics and electrical equipment in the room. Move them to a safe, dry location.
Stop the flow of water, if possible, by turning off the main water supply to the house.
Contact a plumber or water extraction company, if necessary, for assistance.
Remove as much standing water as possible from inside the home.
Begin to remove water-damaged materials immediately.
Ventilate the home to the best possible extent with fans and/or dehumidifiers.

Tampa Home Inspector

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Automatic Pool Sanitizers - The Basics

Chlorine and bromine generators

These electrical units generate chlorine or bromine from special salts added to the water; some units regenerate a bromine bank already in the water. Chlorine and bromine generators are great for maintaining a sanitizer residual, although periodic shocking is still required.As water passes through a chlorine or bromine generator, a sensor measures the sanitizer level. If it is law, the unit starts producing more sanitizer from special salts in the water. Once the sanitizer level is in the proper range, the sensor tells the unit to stop producing chlorine or bromine.

Ozonators

An ozonator produces and releases ozone — an effective sanitizer — into pool or spa water. However, ozone doesn’t last long in a water environment. Once it kills bacteria, the ozone reverts to oxygen and either dissolves into the water or escapes into the air. There’s no way to maintain a measurable ozone residual to ensure the water is sanitized as new contaminants are introduced. Therefore, an ozonator must be used in conjunction with small amounts of chlorine or bromine. There are two types of ozonators: UV and corona discharge. A UV unit creates ozone with a special lightbulb, which needs to be replaced after many months. A corona discharge unit has a special cell that produces ozone. Corona discharge ozonators cost more than UV ozonators, but they don’t have any bulbs that need replacing.

Ionizers

As water flows through these electrical devices, they introduce silver, copper, and zinc ions into the water. These ions are powerful sanitizers. Like ozone, however, there’s no way to maintain a measurable ion residual in the water, so ionizers must be used in conjunction with a halogen-based sanitizer to guarantee a sanitizer residual.

Mineral purifiers

These devices use a combination of silver, copper, and zinc to sanitize water. Some mineral purifiers are simply perforated cylinders that fit inside cartridge filters, whereas others are plumbed in-line along with the other pool equipment. As water flows through a purifier and over the mineral bed, it picks up ions that kill bacteria. Mineral purifiers last several months, but they do not create a sanitizing residual, so they must be used with chlorine or bromine.

Tampa Home Inspector

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Lightning and Surge Protection

Posted January 22, 2007 by Michael
Categories: ASHI Home Inspection, ASHI Home Inspector, Certified Home Inspection, Certified Home Inspector, Florida Home Inspector, Home Inspection, Home Inspection Florida, Home Inspection Tampa, Home Inspector, Home Inspector Florida, Home Inspector Tampa, Licensed Home Inspector, Tampa Home Inspector

Lightning Protection Systems

A well designed lightning protection system will carry a lightning charge through lightning rods and cables on your home down to the ground and safely dissipate it. An effective system should even extend to nearby trees, outbuildings, and other structures that might attract a lightning strike. Another concern, however, is the possibility of damage caused by a power surge through your utility lines. A power surge from a lightning strike miles away can still damage your electronic equipment and telephone system.

To protect against a power surge, it is necessary to stop the surge from entering the house wiring at the main panel. This can he accomplished by installing a whole-house surge arrestor at the main panel and using individual surge arrestors, or suppressors, at points of use that protect each device or appliance at its outlet. To work properly, a surge protection system must also be well grounded because excess current is diverted back through your home’s grounding system and into the earth. A good lightning and surge suppression system will offer little comfort, though, if you’re hit by a major power outage lasting for days. For this, it is wise to have an optional standby generator as a backup source of emergency power.

A lightning strike occurs after a buildup of negative charges of electrical energy in a cloud and positive charges of electrical energy in the earth. As the dry air between the cloud and the ground becomes moist, negative charges move downward to meet positive charges moving upward, creating a lightning bolt. Lightning descends to earth in 150-foot steps. When a negatively charged strike is within 150 feet of a lightning rods, the positive charges in the earth surge upward through the lightning protection system to meet and neutralize the strike. An effective lightning protection system creates a cone of protection around a house. The positive charges flow safely from the ground through the cable to the lightning rod, then jump to the negatively charged lightning strike from the rod, not the surface of the house. Lightning rods are usually from 10 to 12 inches long, and contrary to myth, don’t attract lightning to your home because they’re not much higher than the roofline.

A lightning protection system provides a clear path for lightning to travel directly to the ground without causing injury or destruction to life or property. It consists of three major components: (1) lightning rods, or air terminals; (2) grounding rods, or grounding terminals; and (3) copper or aluminum low-resistance conductor cable to connect the terminals. Copper and aluminum components are used not only because they are excellent conductors of electricity but also because they are highly resistant to corrosion. Copper is preferred because it conducts electricity better than aluminum and less is needed to carry the same amount of current. However, aluminum is necessary on an aluminum or steel roof because copper coming into contact with aluminum or steel can cause corrosion. Nevertheless, even where aluminum is used, the grounding system must be copper. Aluminum cannot be used underground and must be spliced into the grounding wire at least 18 inches above the ground [NEC Section 250.64(A)].

Surge Protection Systems

The major drawback to a lightning protection system is that lightning rods cannot stop electrical surges from coming into a house through utility lines, which is the most common way that lightning damages homes. Transient electrical currents from telephone, cable, and telecommunications lines can cause undesirable surges in voltage. The magnetic field created by a lightning bolt can cause voltage to flow through any conducting material such as the wiring or metal piping in your home. Therefore, an effective surge protection system is a necessity in every home, if it is to be safeguarded against these kinds of potential disruptions.

Whole-House Protection

Many people install low-cost surge arresters, or suppressors, that plug directly into an outlet, believing they are providing themselves with whole-house protection. Unfortunately, this is not the case. Surge suppression must be accomplished on two levels. First is at the main panel, where the surge can be prevented from entering the house wiring, and the second is at the point-of-use, where any surge remaining on a line can be removed just before it enters an appliance or other electrical device. Clearly, it makes sense to use a surge arrester to eliminate heavy surges before they enter your home, rather than after. A surge arrester will divert heavy electrical surges into your grounding system, permitting your point-of-use devices to serve as sensitive electronic filters, shutting down noise on the line, as well as stopping any remaining line surges. If your home has a sub-panel located 20 feet or more from the main panel, you should install a second device to protect it, too. In addition, some lightning protection systems may have a box devoted solely to the system that can be mounted adjacent to the main panel. This type of box contains modular electronics that are replaceable should they be destroyed by a lightning surge passing through the box. In effect, the box is sacrificed to protect your home.

Surge arresters may be directly wired to the main panel and mounted either on the inside or outside of the panel box. The type that mounts outside the panel box is usually preferred in order to protect the breakers and curcuits from explosive discharge. A better system for containing lightning surges, and the easiest to install, is a whole-house protection system in which the surge arrester replaces a circuit breaker in the main panel. Because you have to have a circuit breaker anyway, it makes sense to build the protection directly into it. This type of breaker has a red light that indicates whether or not the surge arrester is functional. Once you install the device, whatever it is wired to will be automatically protected. Though the protection system is contained within the device for a particular circuit, the entire house will be protected—not just that circuit.

Point-of-Use Protection

Providing surge protection directly at an e