CHAPTER 6:

MECHANICAL AND ELECTRICAL REQUIREMENTS

 

General Comments

 

          Chapter 6 establishes minimum criteria for the installation and maintenance of the following:  heating and air-conditioning equipment, appliances and systems; cooking equipment and appliances; ventilation and exhaust equipment; gas and liquid fuel distribution piping and components; fireplaces and solid fuel-burning appliances; chimneys and vents; electrical services; lighting fixtures; electrical receptacle outlets; electrical distribution system equipment, devices and wiring; and elevators, escalators and dumbwaiters.

 

          The primary objectives of mechanical and heating equipment inspections are to detect, identify and abate any condition that is a potential fire or explosion hazard; is a potential cause of asphyxiation or carbon monoxide poisoning; poses the risk of physical injury to an occupant; prevents the equipment from adequately performing its intended function; or that otherwise endangers the occupants or the structure.

 

          The primary objectives of electrical equipment and system inspections are to detect, identify and abate any condition that is a potential fire hazard or electrical shock hazard.  Any condition that inadequately provides for the supply and distribution of electrical power throughout that structure must also be detected, identified and abated.

 

          All mechanical and electrical facilities must be capable of providing the minimum levels of safety, illumination, comfort,  utility and convenience as prescribed in this chapter.

 

 

 

 

 

 

 

 

 

 

          PURPOSE

 

          All mechanical and electrical equipment, appliances and systems must be properly installed to serve the intended purpose.  Proper installation, however, does not in itself guarantee safety or performance.  In addition to proper installation, all such equipment, appliances and systems must be maintained, as they are subject to deterioration, wear and aging, and may require cleaning, lubrication, adjustment, etc.  All materials and components used to construct mechanical and electrical systems have a limited life span, and require repair or replacement at various time intervals that are specific to the material or component.

 

          The purpose of Chapter 6 is to establish minimum performance requirements for electrical and mechanical facilities and to establish minimum standards for the safety of such facilities.

 

SECTION 601

GENERAL

 

601.1 Scope.  The provisions of this chapter shall govern the minimum mechanical and electrical facilities and equipment to be provided.

 

          Minimum performance guidelines for mechanical and electrical facilities and equipment are established in this chapter.  Installations that do not conform to these minimum criteria are unacceptable.

 

601.2 Responsibility.  The owner of the structure shall provide and maintain mechanical and electrical facilities and equipment in compliance with these requirements.  A person shall not occupy as owner-occupant or permit another person to occupy any premises which does not comply with the requirements of this chapter.

 

          It is the responsibility of the owner of the structure to provide and maintain the required electrical and mechanical facilities.  An owner must not occupy or allow any other person to occupy a structure that is not in compliance with this chapter; thus, the requirements of this chapter are the minimum necessary to make a structure occupiable.

 

 

          602.1 Facilities required.  Heating facilities shall be provided in structures as required by this section.  This section establishes the scope of requirements in Section 602 [see the International Mechanical Code (IMC) for space-heating requirements for new structures].

 

          602.2 Residential occupancies.  This section establishes the following minimum requirements for space heating in residential structures.

 

          Adequate heat is required for human health and comfort.  The elderly, infirm and very young are most susceptible to illness and death from inadequate space heating.

 

          Heating equipment must be provided and maintained by the owner and must be able to heat all habitable rooms, bathrooms and toilet rooms to at least 68°  F (20°  C) based on the outside design temperature established for each locality adopting the code.  68°  F  (20° C)  is believed to be the minimum indoor temperature at which people can be reasonably comfortable and can maintain healthy living.  This is intended as an absolute minimum since most dwelling occupants will seek indoor temperatures 5° F to 10° F (-15° C to  -12° C) higher than this.

 

          The outdoor design temperatures are taken from the ASHRAE Handbook of Fundamentals and are listed in Appendix D of the International Plumbing Code (IPC).  Outdoor design temperatures provide a baseline from which heat load calculations are made.  Heating system capacity is dependent upon the predicted outdoor temperatures during the heating season.  As the outdoor temperature falls, the heat input to a building must increase to offset the increasing heat losses through the building envelope.  Heating systems are designed to have the capacity to maintain the desired indoor temperature when the outdoor temperature is at or above  the outdoor design temperature.  When the outdoor temperatures are below the outdoor design temperature, the heating system will not be able to maintain a desired indoor temperature.  It would be impractical, for example, to design a heating system based on the assumption that someday it might be -20° F (-29° C) outdoors if the outdoor temperature in that region rarely, if ever dropped that low.  In such a case, the heating system would be oversized and, thereby, less efficient and economical.

 

          The winter outdoor design temperature is defined as follows:  For 97.5 percent of the total hours in the northern hemisphere heating season, from December through February, the predicted outdoor temperatures will be at or above the values given in Appendix D of the IPC.  It would be unreasonable to expect any heating system to maintain a desired indoor temperature when the outdoor temperature is below the design temperature.  When the 97.5 percent column in Appendix D of the IPC is used, it can be assumed that the actual outdoor temperature will be at or below the design temperature for roughly 54 hours of the total of 2,160 hours in the months of December through February (2,160 hours x 2.5 percent = 54).

 

          The lack of adequate space-heating systems can result in the misuse of cooking appliances.  It is not uncommon for occupants to use fuel-fired ovens and cook-top burners to supply space heating when the minimum required indoor temperature cannot be maintained, and unfortunately, the typical occupant is not aware of the danger in doing so.  Fuel-fired cooking appliances in almost all occupancies are unvented and therefore, discharge all products of combustion directly to the occupied space.  Prolonged use of such appliances can produce dangerously high levels of carbon monoxide and other contaminants, especially considering that the occupants will not be opening windows or operating exhaust systems in an effort to conserve heat.

 

          Also, cooking appliances are not designed for the purpose of space heating, and like all appliances, could be dangerous if used in any way other than intended by the manufacturer.   Cooking appliances are not designed for continuous or unattended use, and open flames, heat radiation and high surface temperatures pose a significant fire hazard when the appliance is misused.

 

          The exception recognizes that in warmer portions of the country, when the average monthly temperature meets or exceeds 30° F (-1° C), the minimum inside temperature can be 65° F(18° C).  As a result of this code requirement, the occupants are ensured of having a comfortable interior environment.

 

 

 

 

          602.3 Heat Supply.  Every owner and operator of any building who rents, leases or lets one or more dwelling units or sleeping units on terms, either expressed or implied to furnish heat to the occupants thereof shall supply heat during the period from October 1^st to May 31^st to maintain a temperature of not less than 68° F (20° C) in all habitable rooms, bathrooms, and toilet rooms.

 

          The owner or operator of rental residential property who agrees to provide heat by express agreement or implication must provide it to all habitable rooms, bathrooms and toilet rooms.  The heat supply must be capable of maintaining a temperature of at least 68° F (20° C), 24 hours per day.  The occupants could set the temperature in the space under their control at a lower temperature if desired, but 68° F (20° C) must be attainable.  Based on local climatic conditions, each community needs to establish the period of the year during which heating equipment must be in operation in order to maintain the required temperatures.  The intent of this section is to protect tenants from being subjected to uncomfortable and unhealthy conditions created by undersized, malfunctioning, defective or otherwise inadequate space-heating systems.  Having adequate space heating also helps eliminate the need for auxiliary room/space heaters, as well as the unsafe use of cooking appliances for space heating (see Section 602.2).  When tenants are forced to use room/space heaters, the risk of fire and asphyxiation increases because of improper use, contact with or close proximity to combustible materials; overloaded wiring and extension cords; lack of ventilation and the user's typical lack of understanding of the potential hazards.

 

          Exception 1 recognizes the limitations of all heating systems that operate when the outdoor temperature is below the design temperature.  This exception states that the minimum indoor temperature requirement of 68° F (20° C) does not apply when the outdoor temperature is below the design temperature for the heating system.  The exception addresses only the circumstance where the heating systems that are operating at their full design capacity (heat output).  It does not apply to improperly designed systems, undersized systems or any system operating at less than its full output for whatever reason.  On those rare days when the outdoor temperature is lower than what the heating system was designed to handle, it is anticipated that the indoor temperature might not be attainable.  Heating systems that were sized based on outdoor temperatures above the actual outdoor design temperature for the locality in which they are installed are improperly designed, and as such, do not comply with the intent of the exception (see commentary, Section 602.2).

 

Exception 2 is the same as the exception to Section 602.2.

 

602.4  Occupiable work spaces.  Indoor occupiable work spaces shall be supplied with heat during the period from October 1^st to May 31^st to maintain a temperature of not less than 65° F (18° C) during the period the spaces are occupied.

 

EXCEPTIONS:

 

1.  Processing, storage, and operation areas that require cooling or special temperature conditions.

 

2.  Areas in which persons are primarily engaged in vigorous physical activities.

 

          Mercantile, business, factory and similar occupancies in which people are employed must be kept at a temperature of at least 65° F (18° C) during the hours that employees are working.  People cannot be expected to work productively and remain in good health if their workplace is uncomfortable.  The 65° F (18° C) minimum is lower than required for residential occupancies and is intended to apply to the typical workplace having sedentary employee activities.

 

          Exception 1 recognizes that some occupancies have operations and processes that require temperatures lower than 65° F (18° C), including meat-packing plants, canneries and manufacturing facilities.

 

          Exception 2 recognizes that a minimum temperature of 65° F (18° C) is not necessary where employees are engaged in physical activities such as construction, fabrication and loading in factories.

 

          The period of the year during which structures must comply with this section is to be established by each locality based on local climatic conditions.

602.5  Room temperature measurement.  The required room temperatures shall be measured 3 feet (914 mm) above the floor near the center of the room and 2 feet (610 mm) inward from the center of each exterior wall.

 

          To determine compliance with Section 602, temperature measurements are required to be taken at multiple locations.  For example, in a room with two exterior walls, a total of three measurements is required.  The room temperature requirements of Section 602 must be met in all of the measurement locations.  The intent is to make sure that the required temperature will be uniformly reached throughout the occupiable portions of the room or space.  The coldest part of a room during the heating season will typically be at the floor level by an outside wall.  The measurements are taken at points that are expected to be occupied and that do not reflect the potential temperature extremes in a space (see Figure 602.5).

 

          Any space that cannot maintain the minimum indoor temperatures established in Section 602 when the outdoor temperature is at or above the design temperature for the locality should be posted as unfit for human occupancy until enough heat can be supplied.

 

SECTION 603

MECHANICAL EQUIPMENT

 

603.1 Mechanical appliances.  All mechanical appliances, fireplaces, solid fuel-burning appliances, cooking appliances and water heating appliances shall be properly installed and maintained in a safe working condition, and shall be capable of performing the intended function.

 

          Because appliances, mechanical equipment and fireplaces are subject to aging, wear and deterioration, periodic inspection and servicing is required to maintain performance and to verify continued safe operation.  Fireplaces and solid fuel-burning appliances must be properly installed, inspected and maintained.  They require frequent inspection and maintenance because of the extreme temperatures and corrosive flue gases to which they are subjected.  Routine cleaning is required to remove the highly flammable creosote  deposits found in chimneys and connectors.  Inspections should include such related items as chimney flues, chimney caps, dampers, doors, screens, connectors, hearth extensions and clearances to combustibles.  Fireplaces and solid fuel-burning appliances must be installed and maintained in accordance with the IMC. 

 

          The appliance manufacturer's  installation instructions and the IMC, International Fuel Gas Code (IFGC) and IPC should be consulted in determining if an appliance and mechanical equipment is installed properly.

 

603.2  Removal of combustion products.  All fuel-burning equipment and appliances shall be connected to an approved chimney or vent.

 

          EXCEPTION:  Fuel-burning equipment and appliances which are labeled for unvented operation.

 

          All fuel-burning appliances are required to discharge the products of combustion (flue gases) to an approved chimney or vent (see exception).  Chimneys and vents must be capable of creating sufficient draft to properly vent the appliances served.  Appliances labeled for unvented operation such as domestic cooking appliances and gas-fired refrigerators are exempt from this requirement.

 

          Some components of the combustion products produced by fuel-burning appliances are toxic to humans and animals and can cause illness and death.  The most harmful component of combustion products is carbon monoxide (CO).  Typical symptoms of CO poisoning are nausea, headache, dizziness, disorientation, confusion, rapid breathing, fatigue, flu-like symptoms and loss of consciousness.  Exposure to CO is detrimental to health in all cases and can be lethal depending upon its concentration, the duration of exposure and the condition of the occupants.  Combustion products must not be allowed to enter or leak into any occupiable or habitable space.

 

          Chimneys and vent should be periodically inspected for deterioration or blockage that could impair their operation or allow combustion products to leak into the building.  The appliance and equipment connections to a chimney or vent should also be inspected for deterioration, blockage and separation of connections.

 

 

 

          Evidence of chimney or vent connector decay or rusting generally indicates improper draft.  A venting system that creates insufficient draft or that is subject to back draft (reverse flow) will experience accelerated deterioration because of the corrosive effect of the combustion products (flue gases).  "Draft" is the pressure differential necessary to cause the flow of flue gases from the appliance or equipment to the chimney or vent and up to the atmosphere.  Proper draft should be verified by a trained heating technician and should be checked each time the appliance or equipment is serviced.

 

          The exception recognizes that a chimney or vent is not required for fuel-burning appliances that are listed and labeled for unvented operation.  It is imperative that unvented appliances be operated and maintained in strict accordance with the manufacturer's instructions (see the IFGC for additional requirements for unvented room heaters).

 

603.3 Clearances.  All required clearances to combustible materials shall be maintained.

 

          Proper clearances must be maintained between combustible materials and all heat-producing appliances and equipment.  Adequate clearances are necessary to prevent the possible ignition of combustibles.  The required clearances for the labeled appliances and equipment must be maintained in accordance with the manufacturer's requirements.  Clearances for chimneys, vents and their connectors are also specified in the IMC and IFGC.

 

          Frequently, an inspector will encounter combustible materials that have been placed too close to heat-producing appliances and equipment after the initial installation.  Combustible storage, furnishings, and remodeling are typical examples of such encounters.  Most occupants are unaware of the hazard created when they store combustibles near or in contact with heat-producing appliances.

 

          It is imperative that adequate clearances be maintained to avoid a potential fire hazard.

 

 

 

 

604.3 Safety controls.  All appliances and heating equipment are equipped with safety controls and devices intended to prevent fire or explosion in the event of equipment malfunction or abnormal operation.  Typical controls and devices are as follows: temperature limit switches; pressure limit switches; pressure relief valves; low-water cut-offs; stack controls; pilot safety controls; draft monitoring controls and flame supervision controls.  These controls are designed to prevent such conditions as overheating, excessive pressures, loss of heat transfer medium, loss of ignition source, loss of venting means and loss of main flame, among others.

 

          All such safety controls must be periodically tested and inspected to verify their proper functioning and assess their reliability.  Such testing and inspection should be performed by trained technicians when the appliances are services and cleaned. 

 

          An inoperative and otherwise malfunctioning safety control or device  could create an extreme life safety hazard.

 

603.5 Combustion air.  A supply of air for complete combustion of the fuel and for ventilation of the space containing the fuel-burning equipment shall be provided for the fuel-burning equipment.

 

          Combustion air includes the air necessary for complete combustion of the fuel, the air required for draft hood dilution and the air necessary for ventilation of the enclosure in which the appliance is located.  A lack of combustion air will result in the incomplete combustion of fuel that, in turn, causes soot production, increased CO production, serious appliance malfunction and the risk of fire or explosion.  The lack of draft hood dilution air will result in improper draft and appliance venting.  The incomplete combustion of fuel and improper draft and venting compound each and greatly increase that, in turn, causes soot production, increased CO production, serious appliance malfunction and the risk of fire or explosion.  The lack of draft hood dilution air will result in improper draft and appliance venting.  The incomplete combustion of fuel and improper draft and venting compound each other and greatly increase the risk of CO poisoning.  The lack of ventilation air can result in excessive temperatures in the appliance enclosure, thereby introducing the risk of overheating the appliance and the risk of fire. 

 

          In existing structures, adequate combustion air provisions are often lacking or have been blocked, covered or otherwise defeated.  Looking for proper combustion air supply is an important part of any inspection.

 

          Fuel-burning equipment must be provided with combustion air in accordance with the IMC.

 

603.6  Energy conservation devices.  Energy saving devices are required to bear the label of an approved testing agency, must be installed in accordance with the manufacturer's installation instructions and must be installed with the specific approval of the Code Official.

 

          Improperly installed or applied energy-saving devices can adversely affect the operation of an appliance and cause it to become unsafe.  A common example would be the improper installation of a flue damper or restrictor device in the chimney or vent connector of a fuel-burning appliance.  The resultant installation could cause vent failure and subject the occupants to CO poisoning.

 

          The installation of such devices would require a permit under the IFGC. 

 

SECTION 604

ELECTRICAL FACILITIES

 

604.1  Facilities required.  This section prescribes the minimum electrical facilities that must be installed and maintained in all buildings used for human occupancy.

 

604.2  Service.  This section prescribes the minimum size of the electrical service that must be provided for all structures.  The electrical service consists of the service entrance conductors, metering devices, service grounding means, main disconnect, main over current device and typically the distribution panel board and all over current devices.  The size of the service is dependent upon the size of the load (demand).  The total electrical usage or load must be determined as prescribed in the International Code Council Electrical Code Administrative Provisions or the International Residential Code (IRC).  Chapter 35 of the IRC provides user-friendly guidance on sizing of services.

          If the actual load exceeds the capacity of the service, additional capacity must be provided.  In no case is the service for a dwelling unit permitted to be less than 60 amperes.  Additionally, all dwelling unit services are to be 120/240 volt (three wire).  The electrical usage in a typical dwelling unit today requires a service of at least a 60-ampere capacity to meet the occupants' needs.  The requirement for a three-wire (120/240 volt) service is intended to allow the use of 240-volt appliances, such as clothes dryers, air conditioners and ranges.  Additionally, appliances that operate at 240 volts consume less current, thereby conserving the remaining capacity of the service.

 

          Overloading or constant loading to capacity subjects the service to excessive heating and component stress.  Not only does this invite failure, but it also increases the risk of fire and creates the inconveniences of a nuisance circuit breaker tripping or fuse blowing.  Nuisance fuse blowing, in turn, encourages the dangerous practice of replacing blown fuses with fuses of larger size.  Over fusing is one of the largest potential causes of fire in any electrical system. 

 

          An inadequately sized service could also restrict the occupants' use of appliances by imposing non-simultaneous use to avoid overloading the service.

 

          A service determined to be undersized in accordance with this section and the requirements of MFPA70 or the IRC must be enlarged as necessary.

 

604.3  Electrical system hazards.  Any electrical system deficiency or condition that is deemed hazardous to the occupants or to the structure must be abated to eliminate the hazard.  Electrical system hazards include, but are not limited to, the following:

 

?             Inadequate (undersized) service;

?             Improper fusing and over current protection;

?             Insufficient receptacle distribution;

?             Lack of sufficient lighting fixtures;

?             Deteriorated, damaged, worn or otherwise defective wiring,        equipment and appliances;

?             Improperly installed or protected wiring methods;

?             Lack of proper service and equipment grounding;

?             Open splices in wiring;

?             Inadequately supported devices, wiring or equipment;

?             Any exposed conductors or components constituting a shock hazard;

?             Missing or damaged device cover plates;

?             Excessive use of extension cords;

?             Overloaded receptacles or circuitry; and

?             Lack of ground fault circuit interrupter (GFCI) protection.

 

          The most commonly encountered hazard is improper over current protection of conductors.  Fuses and circuit breakers are devices designed to limit current flow to the maximum safe current-carrying capacity (ampacity) of a conductor.  With rare exception the conductor's current-carrying capacity (ampacity) must be greater than or at least equal to the ampere rating of the over current device that supplies it.  If a fuse or circuit has a larger ampere-rating capacity than the conductor it is intended to protect, the device will permit the conductor to carry currents in excess of its capacity.  The resultant overload will cause conductor heating, insulation deterioration and, possibly, a fire.   The typical scenario is the occupant who thinks he or she has "cured" a fuse-blowing problem by substituting fuses that are larger in size.  This appears to alleviate the problem for the occupant but, in actuality, an extreme fire hazard has been created by eliminating the circuit conductor over current protection.

 

SECTION 605

ELECTRICAL EQUIPMENT

 

605.1  Installation.  This section provides necessary safety requirements for electrical equipment, wiring and appliances.

 

          All electrical equipment, wiring and appliances must be properly installed and maintained in accordance with this code and NFPA 70 or the IRC.  It is the responsibility of the building owner or operator to provide and safely maintain the electrical facilities required herein.

 

605.2  Receptacles.  Every room or space in a dwelling unit that is used for living, sleeping, eating or cooking must be provided with at least two separate receptacle outlets.  Such outlets must be as remote from each other as practicable.  The quantity of receptacles required by this section is less than that required by NFPA 70 for new construction, but is considered a reasonable compromise for existing structures.

 

          This provision is intended to minimize or eliminate the use of extension cords.  The amount of electrical current that any extension cord can safely conduct is limited by the size of its conductors.  This principle is not understood by much of the general population.  As a result, extension cords are commonly overloaded by the connection of either too many appliances or any loads in excess of the cord's capacity.  Overloading extension cords causes an increase in the conductor's temperature.  This increase can exceed the temperature rating of the conductor's insulation, causing it to melt, decompose or burn.  The burning insulation can easily start a fire, and the resultant loss of conductor insulation can cause a short circuit or ground fault that can also act as a source of ignition.  The buildup of heat in an extension cord is often made worse by excessive cord length and by the insulating effect of rugs that often cover these cords.  Extension cords are much more susceptible to physical damage than permanent wiring methods.  Damage to cords increases the likelihood of shorts, ground faults and poor connections, all of which can cause a fire.  In addition to the fire hazard, extension cords pose a tripping hazard to the occupants and, when damaged, pose an electric shock hazard.

 

          Every laundry room is required to have at least one grounded-type receptacle outlet.  The appliances used in a laundry room are of the type that require a grounding conductor for safe operation.  The grounding of appliances is a means of reducing the risk of electrical shock, which can occur when an occupant comes in contact with a defective appliance.  This section appears to allow a GFCI-protected receptacle outlet in lieu of a grounded-type receptacle; however, this is only allowed for very limited circumstances by NFPA 70.  As a general rule, GFIC protection is not a substitute for grounding-type receptacles.

 

          Every bathroom must have at least one receptacle outlet to accommodate the many grooming and personal hygiene appliances that are commonly used in bathrooms.  This requirement also applies to toilet rooms with lavatories that do not contain bathing fixtures, as they could also be used for grooming and personal hygiene purposes.  If a bathroom receptacle outlet has to be installed in order to achieve compliance with this section, this code, NFPA 70 and the IRC, all would require GFCI protection for such outlet.

          The installation of a receptacle where one previously did not exist is considered new work and must comply with the provisions of NFPA 70 or the IRC.

 

605.3 Luminaries.  Permanent lighting outlets must be provided to illuminate halls, stairways, toilet rooms, bathrooms, laundry rooms, kitchens and furnace and boiler rooms.  The activities in such spaces are not compatible with portable lighting such as floor or table lamps; therefore, permanent lighting outlets (fixtures/luminaries) are required.  In all other spaces, it is assumed that the occupants will provide lamps or other portable fixtures to meet their artificial lighting needs when natural lighting does not exist.  Adequate lighting is necessary for occupants to traverse stairs and corridors without undue hazard; to allow for the proper use of plumbing fixtures and appliances; and to allow for servicing of appliances.

 

          Furnace and boiler rooms are defined terms in the IMC, and the term "furnace room" also applies to a room containing a water heater.

 

SECTION 606

ELEVATORS, ESCALATORS AND DUMBWAITERS

 

606.1  General.   Elevators, escalators and dumbwaiters must be maintained in compliance with ASME A17.1, Safety Code for Elevators and Escalators with A17.1a 2002 Addenda.  ASME 17.1 contains requirements for periodic inspection and testing that are necessary to detect any possible defects.  The safety of the occupants is dependent upon routing safety checks performed by competent elevator service technicians.

 

          Displaying the certificate of inspection is an aid to building inspectors and provides the users of the machinery with some confidence in its safety.  This requirement will also encourage the owner to obtain the required inspections.

 

 

 

 

 

 

 

SECTION 607

DUCT SYSTEMS

 

607.1  General.  Exhaust ducts for toilet rooms, bathrooms, kitchens and clothes dryers require maintenance to prevent blockages and obstructions that can cause appliance/equipment malfunction, poor performance and potential fire hazards.  Heating, cooling and ventilation ducts also need to be maintained to allow proper airflow, to maintain proper HVAC equipment operation and to help eliminate air-borne contaminants that could cause health hazards.  Ducts can collect hazardous quantities of grease, lint, dust and debris that could be potential fire hazards.  Duct systems of all types are typically ignored by building owners and occupants and thus receive little or no maintenance.