by Nick Gromicko, CMI®

A wood-burning stove (also known as a wood stove) is a heating appliance made from iron or steel that is capable of burning wood fuel. Unlike standard fireplaces, wood stoves are typically contained entirely within the living space, rather than inset in the wall.Photo courtesty of Wood-Stoves.org

Wood stoves come in many different sizes, each suited for a different purpose:

  • Small stoves are suitable in single rooms, seasonal cottages or small, energy efficient homes. These models can also be used for zone heating in large homes where supplemental heating is needed.
  • Medium-size stoves are appropriate for heating small houses or mid-size homes that are intended to be energy-efficient and as inexpensive as possible to maintain.
  • Large stoves are used in larger homes or older homes that leak air and are located in colder climate zones.

To ensure safe and efficient use of wood-burning stoves, inspectors can pass along the following tips to their clients:

Never:

  • burn coal. Coal burns significantly hotter than wood, posing a fire hazard;
  • burn materials that will emit toxic chemicals, such as wood that has been pressure-treated or painted, colored paper, gift wrap, plastic, plywood, particleboard, or questionable wood from furniture;
  • burn wet wood. Generally speaking, it takes six months for cut, stored wood to dry out and be ready for use in wood-burning stoves;
  • burn combustible liquids, such as kerosene, gasoline, alcohol or lighter fluid;
  • let small children play near a lit wood-burning stove. Unlike standard fireplaces, the sides of which are mostly inaccessible, all sides of wood stoves are exposed and capable of burning flesh or clothing; or
  • let the fire burn while the fire screen or door is open.

Always:

  • use a grate to hold the logs so that they remain secured in the stove and the air can circulate adequately to keep the fire burning hot;
  • keep the damper open while the stove is lit;
  • dispose of ashes outdoors in a water-filled, metal container;
  • check smoke alarms to make sure they are working properly; and
  • periodically remove the stovepipe between the stove and the chimney so that it can be inspected for creosote. Homeowners may want to hire a professional to perform this service.

Efficiency and Air PollutantsWood-burning stoves account for the smoke pictured in this photo taken in Chico, CA

While federal and state governments crack down on vehicle and industrial emissions, they do relatively little to limit the harmful air pollution emitted from wood stoves. The problem is so bad that, in many areas, such as Chico, Caifornia (pictured at right), the smoke from wood stoves is the largest single contributor to that city’s air pollution.  Smoke from wood stoves can cause a variety of health ailments, from asthma to cancer.

To mitigate these concerns, the EPA sets requirements for wood-stove emissions based on the design of the stove: 4.1 grams of smoke per hour (g/h) for catalytic stoves, and 7.5 g/h for non-catalytic stoves. Some state laws further restrict airborne particulates, and many new models emit as little as 1 g/h. These two approaches — catalytic and non-catalytic combustion — are described briefly as follows:

  • In catalytic stoves, the smoky exhaust passes through a coated, ceramic honeycomb that ignites particulates and smoke gasses. Catalysts degrade over time and must eventually be replaced, but they can last up to six seasons if the stove is used properly. Inadequate maintenance and the use of inappropriate fuel result in an early expiration of the catalyst. These stoves are typically more expensive than non-catalytic models, and they require more maintenance, although these challenges pay off through heightened efficiency.
  • Non-catalytic stoves lack a catalyst but have three characteristics that assist complete, clean combustion:  pre-heated combustion air introduced from above the fuel; firebox insulation; and a large baffle to create hotter, longer air flow in the firebox. The baffle will eventually need to be replaced as it deteriorates from combustion heat.

The following indicators hint that the fire in a wood-burning stove suffers from oxygen deprivation and incomplete combustion, which will increase the emission of particulates into the air:

  • It emits dark, smelly smoke. An efficient stove will produce little smoke.
  • There is a smoky odor in the house.
  • There is soot on the furniture.
  • The stove is burning at less than 300º F. A flue pipe-mounted thermometer should read between 300º F and 400º F.
  • The flames are dull and steady, rather than bright and lively.

To ensure efficiency, practice the following techniques:

  • Purchase a wood-burning stove listed by Underwriters Laboratories. Stoves tested by UL and other laboratories burn cleanly and efficiently.
  • Burn only dry wood. Wood that has a moisture content (MC) of less than 20% burns hotter and cleaner than freshly cut wood, which may contain half of its weight in water.
  • Burn hardwoods, such as oak, hickory and ash once the fire has started. Softwoods, such as pine, ignite quicker and are excellent fire starters.
  • Make sure the stove is properly sized for the space. Stoves that are too large for their area burn inefficiently.
  • Burn smaller wood rather than larger pieces. Smaller pieces of wood have a large surface area, which allows them to burn hotter and cleaner.
In summary, wood-burning stoves, if properly designed and used appropriately for the space, are efficient, clean ways to heat a home.  This article is from InterNACHI and can be found at https://www.nachi.org/wood-burning-stoves.htm.

by Nick Gromicko, CMI® and Kenton Shepard

Temperature/pressure-relief or TPR valves are safety devices installed on water heating appliances, such as boilers and domestic water supply heaters. TPRs are designed to automatically release water in the event that pressure or temperature in the water tank exceeds safe levels.
If temperature sensors and safety devices such as TPRs malfunction, water in the system may become superheated (exceed the boiling point). Once the tank ruptures and water is exposed to the atmosphere, it will expand into steam almost instantly and occupy approximately 1,600 times its original volume. This process can propel a heating tank like a rocket through multiple floors, causing personal injury and extensive property damage.
Water-heating appliance explosions are rare due to the fact that they require a simultaneous combination of unusual conditions and failure of redundant safety components. These conditions only result from extreme negligence and the use of outdated or malfunctioning equipment.
The TPR valve will activate if either water temperature (measured in degrees Fahrenheit) or pressure (measured in pounds per square inch [PSI]) exceed safe levels. The valve should be connected to a discharge pipe (also called a drain line) that runs down the length of the water heater tank. This pipe is responsible for routing hot water released from the TPR to a proper discharge location.

It is critical that discharge pipes meet the following requirements, which can be found in InterNACHI’s Water Heater Discharge Piping mini-course, at www.nachi.org/education. A discharge pipe should: 
  1. be constructed of an approved material, such as CPVC, copper, polyethylene, galvanized steel, polypropylene, or stainless steel. PVC and other non-approved plastics should not be used since they can easily melt.
  2. not be smaller than the diameter of the outlet of the valve it serves (usually no smaller than 3/4″).
  3. not reduce in size from the valve to the air gap (point of discharge).
  4. be as short and as straight as possible so as to avoid undue stress on the valve.
  5. be installed so as to drain by flow of gravity.
  6. not be trapped, since standing water may become contaminated and backflow into the potable water.
  7. discharge to a floor drain, to an indirect waste receptor, or to the outdoors.
  8. not be directly connected to the drainage system to prevent backflow of potentially contaminating the potable water.
  9. discharge through a visible air gap in the same room as the water-heating appliance.
  10. be first piped to an indirect waste receptor such as a bucket through an air gap located in a heated area when discharging to the outdoors in areas subject to freezing, since freezing water could block the pipe.
  11. not terminate more than 6 inches (152 mm) above the floor or waste receptor.
  12. discharge in a manner that could not cause scalding.
  13. discharge in a manner that could not cause structural or property damage.
  14. discharge to a termination point that is readily observable by occupants, because discharge indicates that something is wrong, and to prevent unobserved termination capping.
  15. be piped independently of other equipment drains, water heater pans, or relief valve discharge piping to the point of discharge.
  16. not have valves anywhere.
  17. not have tee fittings.
  18. not have a threaded connection at the end of the pipe so as to avoid capping.
Leakage and Activation
A properly functioning TPR valve will eject a powerful jet of hot water from the discharge pipe when fully activated, not a gentle leak. A leaky TPR valve is an indication that it needs to be replaced. In the rare case that the TPR valve does activate, the homeowner should immediately shut off the water and contact a qualified plumber for assistance and repair.
Inspectors should recommend that homeowners test TPR valves monthly, although inspectors should never do this themselves. The inspector should demonstrate to the homeowner how the main water supply can be shut off, and explain that it can be located at the home’s main water supply valve, or at the water supply shut-off for the appliance on which the TPR is mounted.
TPR Data Plate Information
  • The pressure at which a TPR valve will activate is printed on a data plate located beneath the test lever. This amount should not exceed the working pressure limit marked on the data plate of the water-heating appliance it serves.
  • The BTU/HR rating marked on the water-heating appliance data plate should not exceed that of the TPR, which is marked on the TPR data plate.
  • TPR valves with missing data plates should be replaced.

Although a TPR valve might never become activated, it is an essential safety component on boilers and domestic water heaters. Guidelines concerning these valves and their discharge pipes reflect real hazards that every homeowner and home inspector should take seriously. This article is from InterNACHI and can be found at https://www.nachi.org/tpr-valves-discharge-piping.htm.

by Nick Gromicko, CMI® and Kenton Shepard

Knob-and-tube (K&T) wiring was an early standardized method of electrical wiring in buildings, in common use in North America from about 1880 to the 1940s. The system is considered obsolete and can be a safety hazard, although some of the fear associated with it is undeserved.

InterNACHI inspectors should always disclaim knob-and-tube wiring during their inspections.

Facts About Knob-and-Tube Wiring:Knob and Tube Wiring

  • It is not inherently dangerous. The dangers from this system arise from its age, improper modifications, and situations where building insulation envelops the wires.
  • It has no ground wire and thus cannot service any three-pronged appliances.
  • While it is considered obsolete, there is no code that requires its complete removal.
  • It is treated differently in different jurisdictions. In some areas, it must be removed at all accessible locations, while others don’t, but inspect it for safety reasons.
  • It is not permitted in any new construction.

How Knob-and-Tube Wiring Works:           

K&T wiring consists of insulated copper conductors passing through lumber framing drill-holes via protective porcelain insulating tubes. They are supported along their length by nailed-down porcelain knobs. Where wires enter a wiring device, such as a lamp or switch, or were pulled into a wall, they are protected by flexible cloth or rubber insulation called “loom.”

Advantages of Knob-and-Tube Wiring:

  • K&T wiring has a higher ampacity than wiring systems of the same gauge. The reason for this is that the hot and neutral wires are separated from one another, usually by 4 to 6 inches, which allows the wires to readily dissipate heat into free air.
  • K&T wires are less likely than Romex cables to be punctured by nails because K&T wires are held away from the framing.
  • The porcelain components have an almost unlimited lifespan.
  • The original installation of knob-and-tube wiring is often superior to that of modern Romex wiring. K&T wiring installation requires more skill to install than Romex and, for this reason, unskilled people rarely ever installed it.

Problems Associated with K&T Wiring:

  • Unsafe modifications are far more common with K&T wiring than they are with Romex and other modern wiring systems. Part of the reason for this is that K&T is so old that more opportunity has existed for improper modifications.
  • The insulation that envelopes the wiring is a fire hazard.
  • It tends to stretch and sag over time.
  • It lacks a grounding conductor. Grounding conductors reduce the chance of electrical fire and damage to sensitive equipment.
  • In older systems, wiring is insulated with varnish and fiber materials that are susceptible to deterioration.

Compared with modern wiring insulation, K&T wiring is less resistant to damage.  K&T wiring insulated with cambric and asbestos is not rated for moisture exposure. Older systems contained insulation with additives that may oxidize copper wire. Bending the wires may cause insulation to crack and peel away.

K&T wiring is often spliced with modern wiring incorrectly by amateurs. This is perhaps due to the ease by which K&T wiring is accessed.

Building Insulation:

K&T wiring is designed to dissipate heat into free air, and insulation will disturb this process. Insulation around K&T wires will cause heat to build up, and this creates a fire hazard. The 2008 National Electrical Code (NEC) requires that this wiring system not be covered by insulation. Specifically, it states that this wiring system should not be in…

hollow spaces of walls, ceilings and attics where such spaces are insulated by loose, rolled or foamed-in-place insulating material that envelops the conductors.

Local jurisdictions may or may not adopt the NEC’s requirement. The California Electrical Code, for instance, allows insulation to be in contact with knob-and-tube wiring, provided that certain conditions are met, such as, but not limited to, the following:

  • A licensed electrical contractor must certify that the system is safe.
  • The certification must be filed with the local building department.
  • Accessible areas where insulation covers the wiring must be posted with a warning sign. In some areas, this sign must be in Spanish and English.
  • The insulation must be non-combustible and non-conductive.
  • Normal requirements for insulation must be met.

Modifications:Knob and Tube Wiring on thermal insulation

When K&T wiring was first introduced, common household electrical appliances were limited to little more than toasters, tea kettles, coffee percolators and
clothes irons. The electrical requirements of mid- to late-20th century homes
could not have been foreseen during the late 18th century, a time during which electricity, to many, was seen as a passing fad. Existing K&T systems are notorious for modifications made in an attempt to match the increasing amperage loads required by televisions, refrigerators, and a plethora of other electric appliances. Many of these attempts were made by insufficiently trained handymen, rather than experienced electricians, whose work made the wiring system vulnerable to overloading.
  • Many homeowners adapted to the inadequate amperage of K&T wiring by installing fuses with resistances that were too high for the wiring. The result of this modification is that the fuses would not blow as often and the wiring would suffer heat damage due to excessive amperage loads.
  • It is not uncommon for inspectors to find connections wrapped with masking tape or Scotch tape instead of electrical tape.

K&T Wiring and Insurance:

Many insurance companies refuse to insure houses that have knob-and-tube wiring due to the risk of fire. Exceptions are sometimes made for houses where an electrical contractor has deemed the system to be safe.

Advice for those with K&T wiring:

  • Have the system evaluated by a qualified electrician. Only an expert can confirm that the system was installed and modified correctly.
  • Do not run an excessive amount of appliances in the home, as this can cause a fire.
  • Where the wiring is brittle or cracked, it should be replaced. Proper maintenance is crucial.
  • K&T wiring should not be used in kitchens, bathrooms, laundry rooms or outdoors. Wiring must be grounded in order to be used safely in these locations.
  • Rewiring a house can take weeks and cost thousands of dollars, but unsafe wiring can cause fires, complicate estate transactions, and make insurers skittish.
  • Homeowners should carefully consider their options before deciding whether to rewire their house.
  • The homeowner or an electrician should carefully remove any insulation that is found surrounding K&T wires.
  • Prospective home buyers should get an estimate of the cost of replacing K&T wiring. They can use this amount to negotiate a cheaper price for the house.

In summary, knob-and-tube wiring is likely to be a safety hazard due to improper modifications and the addition of building insulation. Inspectors need to be wary of this old system and be prepared to inform their clients about its potential dangers. This article is from InterNACHI and can be found at https://www.nachi.org/knob-and-tube.htm.

by Nick Gromicko, CMI® and Ben Gromicko

Polyurethane spray foam is a versatile insulation material that is sprayed into building cavities where it quickly expands and molds itself to its surroundings. It is available in “closed-cell” and “open-cell” varieties, each of which offers advantages and disadvantages, depending on the requirements of its application. The following guide briefly explains the differences between these insulation options.Contractor installng spray foam insulation

Closed-Cell Polyurethane Foam

Closed-cell polyurethane foam (CCPF) is composed of tiny cells with solid, unbroken cell walls that resemble inflated balloons piled tightly together. The cells are inflated with a special gas selected to make the insulation value of the foam as high as possible. Like the inflated tires that hold up an automobile, the gas-filled bubbles, when dried, create a material that is strong enough to walk on without major distortion. Wall-racking strength can by enhanced when CCPF is applied, and its strength makes it preferable for roofing applications. The high thermal resistance of the gas gives CCPF an R-value of approximately R-7 to R-8 per inch, according to the U.S. Department of Energy (DOE), which is significantly better than its open-cell alternative. It also acts as a vapor barrier, making it the product of choice if the insulation is likely to be exposed to high levels of moisture. Its density is generally 2 lb/ft3 (32 kilograms per cubic meter [kg/m3]).

Over time, the R-value of CCPF can drop as some of the low-conductivity gas escapes and is replaced with ordinary air, a process known as thermal drift. Research performed by the DOE revealed that most thermal drift occurs within the first two years after the insulation material is applied, but then the foam remains relatively unchanged unless it is damaged.
Foam is a Fire Hazard
Semi-permeable rigid foam insulation and spray foam insulation (foam plastic) on the inside of basement foundation walls is often found during an inspection of the full-basement foundation of a house.  Its use could be a good strategy for a moisture-resistant finished basement. However, fire and smoke characteristics of this type of insulation require that it be covered with a fire-resistant layer, such as gypsum wallboard (drywall).
Sometimes this requirement works fine when the basement is being finished. This requirement of having spray foam insulation to be protected by a thermal barrier is found in the International Residential Code (IRC) 2015 Section R316. In most cases where spray polyurethane foam insulation is installed, the foam should be separated from the interior living spaces by an approved thermal barrier of at least 1/2-inch gypsum wallboard (drywall), 23/32-inch wood structural panel, or a material tested to meet the acceptable criteria from NFPA. There are a few exceptions to this requirement, including flame spread index ratings.
If a basement will only be insulated and not finished, a fire-rated foam panel or similar fire-rated covering needs to be used. Because the above-grade portions of the basement wall can dry to the outside, fire-rated insulation on these surfaces may be of an impermeable type. For example, it can have a foil facing.  But insulating approaches that restrict the drying potential of below-grade portions of the foundation wall toward the inside should be avoided.

In attics, a thermal barrier is not required when several conditions exist. Those conditions are listed within the IRC Code 2015 Section R316, and they include the attic access is required, the attic space is entered for only maintenance and when repairs are needed, and the foam insulation has been tested or the foam insulation is protected again ignition using a listed barrier material.

Packages and containers of spray foam insulation (or foam plastic) should be labeled and identified if they are delivered to a building site.

Open-Cell Polyurethane Foam

Open-cell polyurethane foam (OCPF) is a soft, flexible, spongy insulation with broken cell walls that permit air to fill them. They typically have a density of 0.5 lb/ft3 (8 kilograms per cubic meter [kg/m3]), which is significantly less than closed-cell insulation, as well as having a reduced R-value per inch, although OCPF still has excellent thermal-insulating and air-barrier properties. The foam is weaker and less rigid than closed-cell foams, too. It will require trimming and disposal of excess material as it expands to over 100 times its initial liquid size.

Builders often choose open-cell foam for the following advantages it affords, including:

  • its low cost. Where economical yield is important, open-cell foam is generally chosen over its more costly alternative;
  • providing a sound barrier. OCPF forms a more effective sound barrier in normal-frequency ranges than closed-cell foam. For this reason, OCPF is well-suited for installation beneath floors and around theater rooms;
  • its flexibility. Open-cell foam is more flexible than closed-cell foam, which allows it to adjust to weather-induced expansion and contraction of framing members. CCPF, by contrast, may develop hairline fractures because it cannot flex sufficiently; and
  • its permeability to moisture. While often cited as a reason to avoid the use of OCPF, in certain situations, it can be helpful for moisture to pass through insulation. Open-cell foam used in roofs, for instance, will allow a roof leak to make its way to the space below where it is more likely to be discovered. Closed-cell foam used in the same application would trap the moisture, hiding the leak and potentially leading to wood decay. In most situations, however, OCPF should not be used in any place where it might become wet, as moisture will diminish its insulative value. InterNACHI inspectors may call out open-cell insulation discovered in moist areas, such as in external applications or below grade.
In summary, polyurethane foam is available in two varieties that are suited for different applications.  This article is from InterNACHI and can be found at https://www.nachi.org/polyurethane-spray-foam.htm.

by Nick Gromicko, CMI®

A pilot light is a small flame that is kept alight constantly in order to serve as an ignition source for a gas burner. They are used on many natural gas and propane appliances, such as water heaters, clothes dryers, central heating systems, fireplaces and stoves. Pilot lights are used as an ignition source for some fuel-burning appliances

The pilot light is fueled by a small amount of gas released from the gas pipe. When the appliance is turned on, a valve releases more gas, which is ignited by the pilot light. The light may need to be re-lit from time to time after being extinguished on purpose or by accident. Modern alternatives to the pilot light include a high-voltage electric arc between two electrodes placed close to the gas flow, and a red-hot surface made from silicon carbide, silicon nitride, or another material that can withstand prolonged heat exposure. While most commercial kitchens still rely on pilot lights for ovens and grills, their residential counterparts typically use electrical ignitions.

Safety

If a pilot light is accidentally extinguished, there exists a danger that the gas used to keep the flame lit will continue to vent, possibly into the living space. If this leak continues, its concentration may reach a point where a spark – such as that from a cigarette lighter, static electricity, or even the pilot light itself as it is re-lit – will cause a fire or even an explosion. As a precaution, the flow of gas to the pilot light is maintained by electrical circuitry that relies on the detection of the flame by a sensor.
Modern appliances that use pilot lights should be equipped with one or more of the following sensors types:
  • a photo-resistor, which detects the light emitted by the pilot light;
  • a thermometer, which detects the heat created by the pilot light; or
  • a voltmeter, which detects the electrical current created by the heat of the flame as it warms a thermocouple.  A thermocouple is a device that creates a voltage related to the temperature difference at the junction of two different metals.

Natural gas and propane can usually be detected by building occupants by their odor, which is added to these naturally odorless fuels specifically to alert people to a lurking danger. Numerous injuries have been reported, however, when homeowners have tried to re-light a pilot light after the appliance’s malfunctioning sensor failed to stop the flow of gas into the room. Thermocouples are degraded by continued exposure to the pilot light’s flame, which increases their electrical resistance and reduces their effectiveness as flame sensors. Periodic testing and replacement of these devices will mitigate the safety hazards posed by pilot light-equipped appliances.

While many inspectors and homeowners may not be aware of the danger, a number of houses are destroyed every year when a pilot light ignites the explosive gasses released from insecticide “bug bombs” and foggers. A fire erupted in a Newburgh, Ohio house after a man placed a roach fumigator under his kitchen sink and the fumes reached his oven’s pilot light. Even worse, when homeowners employ a recklessly large number of these foggers, they can generate enough gas to create a catastrophic explosion, and the determination of homeowners driven mad by cockroaches and fleas is occasionally enough incentive for them to employ such overkill. In one case, 19 foggers were Bug bombs were detonated by a pilot light, destroying this small San Diego homeunleashed in a 470-square foot San Diego home, filling the building with so much gas that the pilot light destroyed the home and launched shrapnel into the street. Fortunately, foggers are typically used in buildings that have been vacated. Three men were hospitalized, however, when an oven’s pilot light in a Thai restaurant in Perth, Australia ignited the gas released from 36 foggers – enough to blow the roof off the building in a massive explosion that rocked the suburban neighborhood, causing $500,000 in damages.

Energy Waste

Pilot lights are not needed for the majority of the time that they’re lit, which is how they waste a large amount of fuel. The exact amount of energy wasted depends on the unit, but various studies report that a pilot light burns $7.50 to $18 per month of natural gas, and even more for propane-fueled appliances. They waste more than 20% of the gas used in the United States, according to Cornell Environmental Health and Safety. A constantly burning pilot light also adds heat to the house, which might be useful in the winter, but adds to the heat load in the summer and places an unnecessarily greater burden on the air-conditioning system. Even in the winter, the appliance may be located in a utility room or other area that doesn’t require heating. Also, a typical pilot light can generate 450 pounds of carbon dioxide – a greenhouse gas — over a six-month period.

If an appliance isn’t needed for a long period of time, its pilot light may be extinguished to save energy, reduce greenhouse gas emissions, and reduce the risk of fire or explosion. Concerned homeowners can also purchase appliances equipped with the aforementioned alternatives to the pilot light. If they have any additional issues or concerns related to pilot lights or fuel-burning appliances, they should consult with an InterNACHI inspector during their next scheduled inspection.

In summary, pilot lights are a somewhat antiquated technology plagued by fears concerning fire and energy waste.  This article is from InterNACHI and can be found at https://www.nachi.org/pilot-lights.htm.

You can schedule you home inspection with Red Horse Home Inspection online.  Follow us on Facebook to see our newest post.

by Nick Gromicko, CMI® and Ethan Ward

What is a GFCI?

A ground-fault circuit interrupter, or GFCI, is a device used in electrical wiring to disconnect a circuit when unbalanced current is detected between an energized conductor and a neutral return conductor.  Such an imbalance is sometimes caused by current “leaking” through a person who is simultaneously in contact with a ground and an energized part of the circuit, which could result in lethal shock.  GFCIs are designed to provide protection in such a situation, unlike standard circuit breakers, which guard against overloads, short circuits and ground faults.
It is estimated that about 300 deaths by electrocution occur every year, so the use of GFCIs has been adopted in new construction, and recommended as an upgrade in older construction, in order to mitigate the possibility of injury or fatality from electric shock.

History

The first high-sensitivity system for detecting current leaking to ground was developed by Henri Rubin in 1955 for use in South African mines.  This cold-cathode system had a tripping sensitivity of 250 mA (milliamperes), and was soon followed by an upgraded design that allowed for adjustable trip-sensitivity from 12.5 to 17.5 mA.  The extremely rapid tripping after earth leakage-detection caused the circuit to de-energize before electric shock could drive a person’s heart into ventricular fibrillation, which is usually the specific cause of death attributed to electric shock.

Charles Dalziel first developed a transistorized version of the ground-fault circuit interrupter in 1961.  Through the 1970s, most GFCIs were of the circuit-breaker type.  This version of the GFCI was prone to frequent false trips due to poor alternating-current characteristics of 120-volt insulations.  Especially in circuits with long cable runs, current leaking along the conductors’ insulation could be high enough that breakers tended to trip at the slightest imbalance.
Since the early 1980s, ground-fault circuit interrupters have been built into outlet receptacles, and advances in design in both receptacle and breaker types have improved reliability while reducing instances of “false trips,” known as nuisance-tripping.

NEC Requirements for GFCIs

The National Electrical Code (NEC) has included recommendations and requirements for GFCIs in some form since 1968, when it first allowed for GFCIs as a method of protection for underwater swimming pool lights.  Throughout the 1970s, GFCI installation requirements were gradually added for 120-volt receptacles in areas prone to possible water contact, including bathrooms, garages, and any receptacles located outdoors.

The 1980s saw additional requirements implemented.  During this period, kitchens and basements were added as areas that were required to have GFCIs, as well as boat houses, commercial garages, and indoor pools and spas.  New requirements during the ’90s included crawlspaces, wet bars and rooftops.  Elevator machine rooms, car tops and pits were also included at this time.  In 1996, GFCIs were mandated for all temporary wiring for construction, remodeling, maintenance, repair, demolition and similar activities and, in 1999, the NEC extended GFCI requirements to carnivals, circuses and fairs.

The 2008 NEC contains additional updates relevant to GFCI use, as well as some exceptions for certain areas.  The 2008 language is presented here for reference.

2008 NEC on GFCIs

100.1 Definition

100.1  Definitions. Ground-Fault Circuit Interrupter. A device intended for the protection of personnel that functions to de-energize a circuit or portion thereof within an established period of time when a current to ground exceeds the values established for a Class A device.

FPN: Class A ground-fault circuit interrupters trip when the current to ground has a value in the range of 4 mA to 6 mA.  For further information, see UL 943, standard for Ground-Fault Circuit Interrupters.

210.8(A)&(B)  Protection for Personnel

210.8 Ground-Fault Circuit Interrupter Protection for Personnel.

(A)  Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.

(1)   bathrooms;

(2)   garages, and also accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use;

Exception No. 1: Receptacles not readily accessible.

Exception No. 2: A single receptacle or a duplex receptacle for two appliances that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G)

(3)   outdoors;

Exception: Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow melting or deicing equipment shall be permitted to be installed in accordance with the applicable provisions of Article 426.

(4)   crawlspaces at or below grade level.

Exception No. 1: Receptacles that are not readily accessible.

Exception No. 2:  A single receptacle or a duplex receptacle for two appliances that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Exception No. 3: A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have ground-fault circuit interrupter protection.

Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G)

(6)   kitchens, where the receptacles are installed to serve the countertop surfaces;

(7)   wet bar sinks, where the receptacles are installed to serve the countertop surfaces and are located within 6 feet (1.8 m) of the outside edge of the wet bar sink;

(8)   boathouses;

(B) Other Than Dwelling Units. All 125-volt, single-phase, 15- and 20-ampere receptacles Installed in the locations specified in (1), (2), and (3) shall have ground-fault circuit interrupter protection for personnel:

(1)   bathrooms;

(2)   rooftops;

Exception: Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or de-icing equipment shall be permitted to be installed in accordance with the applicable provisions of Article 426.

(3)   kitchens.

Testing Receptacle-Type GFCIs

Receptacle-type GFCIs are currently designed to allow for safe and easy testing that can be performed without any professional or technical knowledge of electricity.  GFCIs should be tested right after installation to make sure they are working properly and protecting the circuit.  They should also be tested once a month to make sure they are working properly and are providing protection from fatal shock.
To test the receptacle GFCI, first plug a nightlight or lamp into the outlet. The light should be on.  Then press the “TEST” button on the GFCI. The “RESET” button should pop out, and the light should turn off.
If the “RESET” button pops out but the light does not turn off, the GFCI has been improperly wired. Contact an electrician to correct the wiring errors.

If the “RESET” button does not pop out, the GFCI is defective and should be replaced.

If the GFCI is functioning properly and the lamp turns off, press the “RESET” button to restore power to the outlet.  This article if from InterNACHI and can be found athttps://www.nachi.org/gfci.htm.

by Nick Gromicko, CMI®

Rodents are a problem not just because they can destroy personal property and create problems with a home’s structure, but also because they can spread serious diseases to humans and their pets. Rodent-borne disease may be spread directly — by touching rodents or their Rat in a PVC pipeurine, feces or saliva — or indirectly — by coming into contact with fleas or other insects that have fed on an infected rodent host. Inspectors should use extreme caution and wear appropriate personal protective equipment when entering a home that is known to be infested with rodents.
Some diseases resulting from direct contact with mice and rats include:
  • hantavirus pulmonary syndrome;
  • hemorrhagic fever with renal; syndrome;
  • Lassa fever;
  • leptospirosis;
  • lymphocytic chorio-meningitis;
  • plague;
  • rat-bite fever;
  • salmonellosis;
  • South American arenaviruses; and
  • tularemia.
Some diseases resulting from indirect contact with mice and rats include:
  • babesiosis;
  • Colorado tick fever;
  • human granulocytic anaplasmosis;
  • lyme disease;
  • murine typhus;
  • scrub typhus;
  • rickettsialpox;
  • relapsing fever; and
  • Rocky Mountain spotted fever.

Rodents also pose a danger to the integrity of the structures they inhabit. They have strong teeth and they may chew through structures to gain access to food sources. The best method for preventing exposure to rodents is to prevent rodent infestation in the first place, according to the Centers for Disease Rodent trapControl (CDC) and the U.S. Environmental Protection Agency (EPA).

How can you tell that a home is infested?
Actual rodent sightings in the home are a good indicator that a severe infestation may be in progress.  Mild cases of infestation might not result in actual rodent sightings.
Indicators of an infestation are:
  • chewing or clawing sounds that come from inside or outside a home. Noises may even come from the roof, as tree-dwelling rodents may try to gain access to a home from above the living space;
  • stale smells coming from hidden areas;
  • evidence of structural damage that can provide entry points into the home;
  • evidence of gnawing and chewing on food packaging;
  • nesting material found in small piles, such as shredded paper, fabric or dried plant matter; and
  • rodent droppings anywhere in the home, especially near food packages in drawers and cupboards, and under the sink.
How can rodent infestation be prevented?
The following measures can be taken to eliminate rodents’ food sources, according to the CDC:
  • Keep food in thick plastic or metal containers with tight-fitting lids.
  • Clean up spilled food right away, and wash dishes and cooking utensils soon after use.
  • Keep outside cooking areas and grills clean.
  • Always put pet food away after use and do not leave pets’ food or water bowls out overnight.
  • Keep bird feeders away from the house.  Utilize squirrel guards to limit access to the feeder by squirrels and other rodents.
  • Use thick plastic or metal garbage cans with tight-fitting lids.
  • Keep compost bins as far away from the house as possible.
  • Dispose of trash and garbage on a frequent and regular basis, and eliminate clutter in and around the property to discourage nesting.
Mice can squeeze through a hole the size of a nickel, and rats can squeeze through a hole the size of a half dollar, according to the CDC. Consequently, smaller gaps may be filled cheaply and easily with steel wool and caulk may be used to seal it in place. Larger gaps and holes may be filled with lath screen or lath metal, cement, hardware cloth or metal sheeting.
Common places where gaps may be found inside the home are:
  • inside, under and behind kitchen cabinets, refrigerators and stoves;
  • inside closets near the floor’s corners;
  • around the fireplace;
  • around doors;
  • around plumbing pipes under sinks and washing machines;
  • around the piping for hot water heaters and furnaces;
  • around floor vents and dryer vents;
  • inside the attic;
  • in the basement or crawlspace;
  • near the basement and laundry room floor drains; and
  • between the floor and wall juncture.
Common places where gaps may be found outside the home are:
  • in the roof among the rafters, gables and eaves;
  • around windows;
  • around doors;
  • around the foundation;
  • near attic vents and crawlspace vents;
  • under doors; and
  • around holes for electrical, plumbing, cable and gas lines.
Any potential nesting sites outside the home should be eliminated. Elevate hay, woodpiles and garbage cans at least 1 foot off the ground. Move woodpiles far away from the house. Get rid of old trucks, cars and old tires that mice and rats could use as homes. Keep grass cut short, and keep shrubbery within 100 feet of the home well-trimmed.
What should be done if a house is found to be infested with rodents?
It is important to stay away from rodents, and to protect children and pets from direct and indirect contact if they are found in the home. Droppings should be handled only with extreme caution, even if they have dried. A face mask and gloves should be worn if handling and cleaning up these droppings because disturbing fecal particles may precipitate airborne contaminants. Affected areas should be sterilized after the droppings have been removed.All holes, cracks, and gaps in a home should be sealed to keep out rodents
In mild cases of infestation, homeowners may choose to eliminate the rodents themselves. They should make sure to take preventative measures while doing so.  To remove rodents, homeowners will need to use traps or rodenticides.
Some different types of traps include:
  • lethal traps, such as snap traps, that are designed to trap and kill rodents;
  • live traps, such as cage-type traps, that capture rodents alive and unharmed, requiring that the rodents then be released or killed; and
  • glue boards, which are low-cost devices that use sticky substances to trap rodents, requiring a further decision regarding disposal, since such traps are not lethal.
Traps should be set in any area where there is evidence of frequent rodent activity. Some rodents, particularly rats, are very cautious and several days may pass before they approach the traps. Other rodents, such as house mice and deer mice, are less cautious and may be trapped more quickly. Glue traps and live traps may scare mice that are caught live, causing them to urinate. This may increase a homeowner’s risk of being exposed to diseases, since the rodent urine may contain germs or disease-borne pathogens.

Rodenticides are products intended to kill rodents, and are typically sold as powders in bait and tracking form.  Some rodenticides include:

  • baits, which combine rodenticides with food to attract rodents.  They may be formulated as blocks or paste and may be enclosed in a bait station;
  • tracking powders, which are rodenticides combined with a powdery material.  The powder sticks to the rodents’ feet and fur and is swallowed when the animals groom themselves.  After consuming the chemical poison contained in the bait or tracking powder, the rodents die.  Some rodenticides (including tracking powders) may be legally applied only by certified pesticide applicators because they may pose a risk to human health.
The following measures should be observed when an infestation is being eliminated:
  • Traps and baits should be placed in areas where children and pets cannot reach them.
  • Products should be used according to the label’s directions and precautions.
  • Only traps that are appropriate to the type and size of the targeted rodent should be used.
  • Glue boards should be placed in dry, dust-free areas, as moisture and dust will reduce their effectiveness.

It is advisable to contact a professional exterminator to deal with more severe infestations, since rodents reproduce constantly and quickly.

In summary, rodent infestation poses a serious risk to human health, and extreme caution must be taken when eliminating the problem.  This article is from InterNACHI and can be found at https://www.nachi.org/rodent-inspection.htm.

Schedule your home inspection with Red Horse Home Inspection of the Black Hills.  Follow us on Facebook and Instagram.

by Nick Gromicko, CMI®

Galvanic corrosion (also known as bimetallic corrosion or dissimilar-metal corrosion) is an electrochemical disintegration that occurs when dissimilar metals come in contact with each other while immersed in an electrolyte. Galvanic corrosion is of major concern anywhere moisture can reach metal building components. Corrosion asGalvanic Corrosion a broader category is defined as the disintegration of a material into its constituent parts, which may be caused by crevice corrosion, microbial corrosion, and high-temperature corrosion.

There are three conditions that must exist for galvanic corrosion to occur:

  • Two electrochemically dissimilar metals must contact one another. They are dissimilar in the sense that they are far apart on the anodic index, which rates metals based on their electrode potentials. Metals that are more active (such as magnesium and zinc) will corrode in the presence of metals that are less active (such as gold and platinum).
  • There must be an electrically conductive path between the two metals. Any non-metal, liquid substance that can conduct an electric current (such as saltwater or rainwater) can function as an electrolyte. Common examples are ordinary seawater, citric acid, and bases.
  • An electrical path must exist to allow metal ions to move from the active metal to the less active metal. Typically, the metals merely touch one another.

The Statue of Liberty is perhaps the most famous case of galvanic corrosion. Contact between the wrought-iron support and the outer copper skin amidst rainwater exposure has allowed the structure to gradually corrode. The famous icon’s builder anticipated this problem and installed asbestos cloth soaked in shellac insulation in the 1880s.  This worked for some time until it dried up and became porous, acting as a sponge that held saltwater close to the contact points between the two metals. An inspection in 1981 revealed severe galvanic corrosion of the iron supports, causing them to swell and push saddle rivets through the copper skin. This rapidly worsening situation was the main drive to restore the statue in 1986, when the iron was replaced with a variety of corrosion-resistant steel. The solution has held up, and native New Yorkers and visitors alike have been able to enjoy a landmark free from corrosion that will last long into the 21st century.

Examples in Houses

  • ACQ (alkaline copper quaternary) lumber includes copper, which can corrode when it comes in contact with common aluminum building nails. With this type of lumber, it’s best to use G185 galvanized steel or stainless steel fasteners, as they will resist corrosion.
  • Aluminum wiring can become compromised. In the presence of moisture, aluminum will undergo galvanic corrosion when it comes into contact with certain dissimilar metals.
  • Piping commonly rusts and corrodes, especially at joints. The failure of pipe thread is commonly caused by corrosion where carbon steel pipe directly meets a brass valve, or where it transitions to copper pipe. Dielectric unions may be installed to separate these metals to resist damaging corrosion in pipe connections.
  • The elements of an electric water heater often rust and fail. The copper sheathe and steel base, if they become wet, may corrode. Installing galvanized unions with plastic nipples on the top of the water heater can prevent corrosion.

Galvanic Corrosion Can be Prevented in the Following Ways

  • Electrically insulate the dissimilar metals. Plastic can be used to separate steel water pipes from copper-based fittings.  A coat of grease can be used to insulate steel and aluminum parts.
  • Shield the metal from ionic compounds. This is often accomplished by encasing the metal in epoxy or plastic, or painting it. Coating or protection should be applied to the more noble of the two metals, if it is impossible to coat both. Otherwise, greatly accelerated corrosion may occur at points of imperfection in the less noble (more active or anodic) metal.
  • Choose metals that have similar potentials. Closely matched metals have less potential difference and, hence, less galvanic current. The best such solution is to build with only one type of metal.
  • Electroplate the metals.
  • Avoid threaded connections, as they are most severely weakened by galvanic corrosion.
In summary, galvanic corrosion is the disintegration of metals in the presence of an electrolyte. It can occur in homes wherever dissimilar, joined metals become damp.  This article is from InterNACHI and can be found at  https://www.nachi.org/galvanic-corrosion.htm.

by Nick Gromicko, CMI® and Kenton Shepard

Carpeted bathrooms are bathrooms that have carpeted floors instead of traditional floor surfaces, such as tile or vinyl. Despite their tendency to foster mold and bacteria, carpets are sometimes installed in residential bathrooms for aesthetic purposes. Carpets should never be installed in bathrooms in commercial buildings.
Advantages of Carpets in Bathrooms
  • They make bathrooms appear more warm and inviting.
  • They are softer than tile and many people find them comfortable on bare feet.
  • Bathroom slip hazards are reduced. It is easier to slip on hard bathroom surfaces, such as tile, than on carpet.
  • Installation is generally quick and inexpensive.
Disadvantages of Carpets in Bathrooms
The pad beneath the carpet may soak up large amounts of moisture.  Some of the common ways that carpets may come into contact with moisture in bathrooms include:
  • Steam from the shower will condense on the carpet.
  • Water splashes from the tub or shower.
  • Water sheds from shower/tub occupants as they step onto the carpet.
  • Water splashes out of the sink.
  • Water drips from the vanity.
  • Water leaks from the toilet.
The presence of moisture in the pad will lead to the growth of decay fungi on the wood or oriented strand board (OSB) sub-floor. The sub-floor will be decayed and weakened by mold. Mold also releases spores that can cause respiratory ailments, especially for those with certain health problems. Inspectors can use moisture meters to determine if there is excess moisture beneath a carpet.

In addition to potential mold growth beneath the carpet, bacteria can accumulate in carpeting that surrounds the toilet. Bacteria are contained in urine, which can be accidentally deflected onto the carpet.

Carpeted Bathrooms in Commercial Buildings
It is against code to install carpet in commercial bathrooms. The 2007 edition of the International Building Code (IBC) states the following concerning carpeted bathrooms in commercial buildings:
In other than dwelling units, toilet, bathing and shower room floor finish materials shall have a smooth, hard, nonabsorbent surface. The intersections of such floors with walls shall have a smooth, hard, nonabsorbent vertical base that extends upward onto the walls at least 4 inches (102 mm).
Recommendations for Clients
The following are recommendations that InterNACHI inspectors can pass on to clients who are experiencing urine- or moisture-related problems with their bathroom carpet:
  • Clean the carpet regularly to remove any mold or urine that may be present.
  • Keep the carpet as dry as possible. Various devices exist that prevent water from bypassing the shower curtain.
  • Install a bathroom fan, if one is not installed already. If a fan is installed, operate it more often.
  • Inspectors can inform their clients about why they are experiencing problems.
In summary, carpets installed in bathrooms can trap moisture and urine, substances that can cause structural damage and health problems.  This article is from InterNACHI and can be found at https://www.nachi.org/carpeted-bathrooms.htm.
Schedule your home inspection with Red Horse Home Inspection of the Black Hills.  Give us a call at 490-2916 or schedule online.  Follow us on Facebook and Instagram.

by Nick Gromicko, CMI®

Water Damage Concerns

Basements are typically the area of a structure most at risk for water damage because they are located below grade and surrounded by soil.  Soil releases water it has absorbed during rain or when snow melts, and the water can end up in the basement through leaks or cracks.  Water can even migrate through solid concrete walls via capillary action, which is a phenomenon whereby liquid spontaneously rises in a narrow space, such as a thin tube, or via porous materials.  Wet basements can cause problems that include peeling paint, toxic mold contamination, building rot, foundation collapse, and termite damage.  Even interior air quality can be affected if naturally occurring gasses released by the soil are being transmitted into the basement.

Properly waterproofing a basement will lessen the risk of damage caused by moisture or water.  Homeowners will want to be aware of what they can do to keep their basements dry and safe from damage.  Inspectors can also benefit from being aware of these basic strategies for preventing leaks and floods.

Prevent water entry by diverting it away from the foundation.

Preventing water from entering the basement by ensuring it is diverted away from the foundation is of primary concern.  Poor roof drainage and surface runoff due to gutter defects and improper site grading may be the most common causes of wet basements.  Addressing these issues will go a long way toward ensuring that water does not penetrate the basement.
Here are some measures to divert water away from the foundation:
  • Install and maintain gutters and downspouts so that they route all rainwater and snow melt far enough away from the foundation of the building to ensure that pooling does not occur near the walls of the structure.  At least 10 feet from the building is best, and at the point where water leaves the downspout, it should be able to flow freely away from the foundation instead of back toward it, and should not be collecting in pools.
  • The finish grade should be sloped away from the building for 10 to 15 feet.  Low spots that may lead to water pooling should be evened out to prevent the possibility of standing water near the foundation.
  • Shallow ditches called swales should be used in conditions where one or more sides of the building face an upward slope.  A swale should slope away from the building for 10 to 15 feet, at which point it can empty into another swale that directs water around to the downhill-side of the building, leading it away from the foundation.

 

Repair all cracks and holes.
If leaks or seepage is occurring in the basement’s interior, water and moisture are most likely entering through small cracks or holes.  The cracks or holes could be the result of several things.  Poor workmanship during the original build may be making itself apparent in the form of cracks or holes.  Water pressure from the outside may be building up, forcing water through walls.  The house may have settled, causing cracks in the floor or walls.  Repairing all cracks and small holes will help prevent leaks and floods.
Here are some steps to take if you suspect that water is entering the basement through cracks or holes:
  • Identify areas where water may be entering through cracks or holes by checking for moisture, leaking or discoloration.  Every square inch of the basement should be examined, especially in cases where leaking or flooding has not been obvious, but moisture buildup is readily apparent.
  • A mixture of epoxy and latex cement can be used to fill small hairline cracks and holes.  This is a waterproof formula that can help ensure that moisture and water do not penetrate basement walls.  It is effective primarily for very small cracks and holes.
  • Any cracks larger than about 1/8-inch should be filled with mortar made from one part cement and two parts fine sand, with just enough water to make a fairly stiff mortar.  It should be pressed firmly into all parts of the larger cracks and holes to be sure that no air bubbles or pockets remain.  As long as water is not being forced through basement walls due to outside pressure, the application of mortar with a standard trowel will be sufficient if special care is taken to fill all cracks completely.
  • If water is being forced through by outside pressure, a slightly different method of patching with mortar can be used.  Surface areas of walls or floors with cracks should first be chiseled out a bit at the mouth of the crack and all along its length.  Using a chipping chisel and hammer or a cold chisel, cut a dovetail groove along the mouth of each crack to be filled, and then apply the mortar thoroughly.  The dovetail groove, once filled, should be strong enough to resist the force of pressure that was pushing water through the crack.

Apply sodium-silicate sealant to the walls and floor.

Once all runoff has been thoroughly diverted away from the foundation, and all cracks and holes have been repaired and no leaking is occurring, a waterproof sealant can be applied as a final measure.

Sodium silicate is a water-based mixture that will actually penetrate the substrate by up to 4 inches.  Concrete, concrete block and masonry have lime as a natural component of their composition, which reacts with the sodium silicate to produce a solid, crystalline structure which fills in all the microscopic cracks, holes and pores of the substrate.  No water vapor or gas will be able penetrate via capillary action because the concrete and masonry have now become harder and denser from the sodium silicate.
Here are some steps and tips for its application:
  • Special care should be taken when applying sodium silicate.  It is an alkaline substance and, as such, can burn skin and eyes if it comes into contact with them.  Inhalation can also cause irritation to the respiratory tract.
  • Sodium silicate must be applied only to bare concrete, concrete block or masonry that has been cleaned thoroughly and is free of any dirt, oil, adhesives, paint and grease.  This will ensure that it penetrates the substrate properly and fills in all microscopic cracks.  It can be applied using a garden sprayer, roller or brush to a surface that has first been lightly dampened with a mop or brush.  Apply two to three coats to the concrete, waiting 10 to 20 minutes between each application.  Concrete block and masonry will take three to four coats, with the same 10 to 20 minutes between applications.  Any excess should then be wiped away.  Sodium silicate should not be over-applied or it will not be completely absorbed by the substrate, leaving a white residue.
  • Paint can then be applied without fear of water vapor getting trapped between the paint and the wall, which could eventually cause blistering and peeling.  Adhesives for tile or floor covering can also be used more effectively, once the substrate has been sealed.
Diverting water away from foundations so that it does not collect outside basement walls and floors is a key element in preventing flooding and water damage.  Ensuring that any water that does end up near basement exteriors cannot enter through holes or cracks is also important, and sealing with a waterproof compound will help prevent water vapor or gas from penetrating, as well.  By following these procedures, the risk of water-related issues in basement interiors can be greatly reduced, protecting the building from damage such as foundation rotting, mold growth, and peeling paint, as well as improving the interior air quality by blocking the transmission of gasses from the soil outside.  This article is from InterNACHI and can be found at https://www.nachi.org/waterproofing-basements.htm.