Q What is the minimum insulation required on the line sets serving a heat pump or air conditioner?
A As listed in Sec M1411.4, piping and fittings used for refrigerant vapor (suction) lines shall have a thermal resistivity of at least R = 2.85 hr. ft2° F/Btu and having external surface permeance not exceeding 0.05 perms when tested in accordance with ASTM E 96.

Q What about seismic strapping for air conditioners and/or heat pumps? Are there requirements?
A The Oregon Mechanical Specialty Code (OMSC), Section 301.15 requires the user of the code to go to the Oregon Structural Specialty Code (OSSC), Section 1621 for seismic requirements. Oregon Residential Specialty Code (ORSC), Section M1307.2 requires (residential) appliances designed to be fixed in position to be fastened or anchored. Additionally, Section M1413.1 requires evaporative coolers (swamp coolers) to be secured to prevent displacement.

Q What are the clearance requirements of heat pumps to property lines and structures?
A The distance from property line is governed by local zoning ordinances. The distance from a structure is governed by the manufacturer’s installation requirements.

Q This question concerns retrofitting an AC unit for row houses without a side yard. We are currently allowing contractors to put the units on the strip of property between the garage entry and driveway slabs. There are two possible problems with this scenario: the strips vary in size, and it may be difficult to keep the entire unit on the owner’s side of the property line.
A Each installation is likely to be different. Check the easement and maintenance agreement. For example, in Portland, the location of outdoor A/C units or heat pumps is governed by the zoning code; front-yard setbacks are prohibited locations.

Q Is some sort of barrier required for heat pumps?
A The OMSC, Section 303.4 states: “Appliance shall not be installed in a location where subject to mechanical damage, unless protected by approved barriers.” And the ORSC, Section 1307.3.1 requires: “Appliances located in garages or carports shall be protected from impact by automobiles.” The code does not require protection for equipment not in the path of a vehicle.

Q Does the code limit the noise level produced by heat pumps and air conditioners?
A No, noise level is not addressed in the code. Check your city ordinance. Generally, it is between 40 and 50 decibels at the property line.

Q Does the code specify a minimum efficiency rating for air conditioners or heat pumps? Are there new requirements?
A Yes, Chapter 13 of the OSSC and Chapter 11 of the ORSC both have minimum efficiency-rating requirements for heat pumps and air conditioners.

Anodeless riser
Q. May an anodeless riser be lengthened on its vertical leg (to bring it above grade) with the addition of ferrous pipe in a sleeve sealed to the riser or wrapping the ferrous pipe with a protective coating?
A. Refer to Chapter 24, in the Dwelling Code. This particular scenario is not specifically identified in the code, however Section G2413.6.1 does regulate the use of an anodeless riser and indicates the need to follow the installation instruction from the manufacturer. Where there is any doubt as to the proper method of installation of these listed and labeled products, the manufacturer should be contacted for verification. Although the panel found nothing in the code specifically prohibiting the extension of an anodeless riser, caution should be taken to ensure the manufacturers warranty is not voided and that other parts of the code are adhered to. (Tri-County Mechanical Code Forum, September, 2004)

Barrier posts
Q. Is a protective post required in a garage for an electric water heater or furnace?

A. Yes. The installation of water heaters, whether electric or fuel-fired, is a plumbing installation and therefore is regulated under the plumbing section of the Dwelling Specialty Code. For specific code requirements on water heater protection see Section P2810.3. For additional information on fuel-fired appliances see Section M1307.3.1 and Figure M1307.2.
(Tri-County Code Forum, December 3, 2003)

Q. Is a barrier required if an air conditioner is added to a furnace and the furnace is not protected?

A. No. The Dwelling Specialty Code, Section 1202.1 allows for additions to existing mechanical systems without having to bring the entire system up to current code.
(Tri-County Code Forum, December 3, 2003)

Bath fans-residential
Q. What materials are acceptable for venting residential bath fans?

A. This question often comes up because of the lack of specific language concerning bathroom exhaust ventilation in the Oregon Dwelling Specialty Code (ODSC). The 2003 ODSC, Section M1501.1 states: "Where exhaust duct construction is not specified in this chapter, such construction shall comply with Chapter 16." Since Chapter 15 does not specifically address exhaust ducting for bathrooms, we must glean the information from the requirements found in Chapter 16. Chapter 16 has general requirements for all ducting and doesn't specifically address "bathroom exhaust" ducts, so to help simplify the intent of the code and to answer commonly asked questions concerning exhaust-fan installations, the following shall apply as a minimum requirement for a "typical" bathroom exhaust installation in a one- and two-family dwelling;

Permits are required for new installations and replacement of a bathroom-type exhaust fans.
Plans are not generally required for exhaust fans installed in a one- or two- family dwelling. However, plans may be required for multi-family installations.
Section R303.3 has specific cubic-feet-per-minute (cfm) rates, which may vary based on room size and whether the fan is intermittent or continuous.
Exhaust fans must be listed and labeled by an approved testing agency, such as Underwriter's Laboratory (UL).
All equipment must be installed according to the manufacturer's instructions and meet minimum code requirements.
All exhaust fans must be equipped with a backdraft damper.
Such systems must vent exhaust directly to the outside, and the point of discharge must be at least 3 feet from any opening (such as a window or door) that allows air entry into occupied portions of the dwelling.
Such systems are not allowed to terminate in the crawlspace, underfloor space or in the attic.
Ducts must terminate at least 10 feet from a forced-air unit fresh-air intake or from an evaporative cooler.
Exhaust ducts may be listed and labeled aluminum (corrugated or smooth); smooth, galvanized steel ducts; or any other factory-made Class 0 or Class 1 duct named in Chapter 16 which is listed and labeled indicating compliance with UL 181, UL 181A or UL 181B.
(Tri-County Code Forum, January 22, 2004)

Boilers
1 Q. Does a unit with more than 199,000 Btu's need an ASME rating? Is this something the mechanical code addresses, or does such an installation require an Oregon boiler permit?

A. The unit requires a boiler permit if it exceeds any of the following: 199,000 Btu, water temperature of 210 degrees F0, 150 pounds of operating pressure, or volume of 120 gallons or greater.
(Tri-County Code Forum, May 30, 2002)

2 Q. If multiple water heaters were piped together for space heating, would Btu's and volume combine to make the system a boiler?

A. No.
(Tri-County Code Forum, May 30, 2002)

3 Q. Please explain B31.3 and B31.9

A. ASME B31.9 refers to building services piping. B31.3 refers to process piping which can include hazardous material piping.
(Tri-County Code Forum, February 28, 2002)

Bonding
Q. When replacing a gas appliance, must we worry about bonding the existing gas lines?

A. This an electrical-code question often asked by mechanical installers. The following issues were previously addressed by the electrical code panel and published in the October-December 2002 News Flash:

Q. When extending gas pipe to non-electrical gas equipment (barbecue, insert), are you required to bond the existing gas pipe connected to an existing gas or electrical appliance?

A. No, unless the alteration creates the potential to be energized.

Q. Are you required to bond existing gas pipe when installing a like-for-like change-out?

A. Yes.

Q. A contractor is replacing an oil furnace with a gas furnace that has new gas piping, and the disconnect remains in place: Is an HVAC/R-licensed installer permitted to bond the gas pipe, even though it is a new gas-pipe installation?

A. Yes. This is part of the installation.

Q. Does a gas appliance that is connected to the electrical system by a cord and plug and utilizing an existing outlet have to be bonded?

A. Yes, it must be bonded. (Tri-County Mechanical Code Forum, September, 2004)

Ceiling Return Air Plenum
Q. Does the reference to "circulating air duct" in C404.1 in the 2002 Oregon Mechanical Specialty Code include above ceiling return air plenums? We have been told yes by one jurisdiction and no by another.

A. No. Plenums, by definition, are air compartments or chambers to which one or more ducts are connected. Although plenums are not considered "circulating air ducts", they are part of the "duct system". See State of Oregon Interpretation C404.1.
(Tri-County Code Forum, December 3, 2003)

Q. Is it legal to route gas piping in an accessible ceiling return plenum?

A. Yes. See Statewide Interpretation No. C404.1.
(Tri-County Code Forum, December 3, 2003)

Combustion Air
Q. Combustion air: Is a single opening as per section M1703.3 and figure M1703.3(1) allowed where the manufacturer's installation instructions require a high and low opening? It seems that maybe the code is ahead of the installation instructions.

A. Refer to M1307.1 and R102.1. A single opening would be allowed if manufacturer's listing and/or warranty is not violated.
(Tri-County Code Forum, December 3, 2003)

Q. The installation instruction for one of our 80 percent furnaces cautions against providing combustion air from areas such as laundry rooms. The manufacturer states that installation of a furnace adjacent to laundry equipment can lead to premature corrosion from chemicals in laundry detergents. Would it be acceptable to draw combustion air from an open basement or garage, which by definition is not a confined space, even though laundry equipment is also located in that space?

A. The unit must be installed according to manufacturer's specifications, but the code panel is in agreement that as long as it is not in a confined space and the area can provide adequate combustion air, the installation described above would not be an issue. The panel believes the intent of the manufacturers' caution statement is to address a small room specifically designated as a laundry room.
(Tri-County Code Forum, April 22, 2004)

Condensate Disposal
Q. A commercial air compressor permitted under the boiler and pressure vessel law has a "condensate" line. Who regulates the point of condensate disposal? If it's the mechanical inspector, would you allow it to go to the exterior to a planting area?

A. There is nothing in the mechanical code that specifically regulates this type of condensate. The boiler code doesn't regulate this part of the pressure vessel either. The condensate from an air compressor is different then the condensate from a mechanical unit. For example, it does not automatically drain, as a condensing unit would. Larger compressors are manually drained on a weekly basis and the amount of condensation is relevantly small compared to the amount dispensed by a mechanical unit. Also, the water is usually fairly dirty (rusty) due to corrosion in the pressure vessel. Typically, these tanks, which are associated with the air compressor, are blown-off weekly to an area designated by the owner of the building as an area not affected by staining from rusty water. This would be an area such as indirectly into a floor drain or to an outside rain drain or area drain. It would not be appropriate to blow off the condensate from a pressure vessel to a sidewalk or driveway or any area where the water might splash onto someone or cause rust damage. There is no physical danger from this type of condensate, so disposing of it in a flower bed or landscaped area is fine.
(Tri-County Code Forum, April 22, 2004)

Condensate Pumps and Piping
Q. Are explosion proof condensate pumps allowed to be installed on the floor of a garage?

A. The One-and Two- Family Dwelling Specialty Code provides specific code requirements for the elevation of appliances in Section 1307.3. Although a condensate pump, by definition would not be considered an appliance, when used in conjunction with heating and/or air conditioning equipment, it becomes an appurtenance to that appliance.

Condensate pumps, used as an appurtenance to a heating/cooling appliance which generates a glow, spark or flame, capable of igniting gasoline vapors and located in a garage shall be installed with burners, burner ignition devices or heating elements and switches at least 18 inches above the floor level. Condensate pumps installed on the floor of the garage must be listed and labeled for installation in a Class 1, Division 2 location, as specified in the NEC, Article 500. An "explosion proof" rating, by itself, does not necessarily mean the equipment will meet this requirement. Listed equipment will be marked to show the class, group (division) and operating temperature or temperature range in which the equipment can be used. The identification numbers are marked on the equipment nameplate.
(Tri-County Mechanical Code Forum November 29, 2001)

Q. We have been allowed to create a barrier or dam around a condensate pump that extends 18 inches off the floor. Will that be allowed in all Tri-County jurisdictions in the future?

A. This is a question of alternate methods and materials. Such installations are subject to approval of the local jurisdiction.
(Tri-County Mechanical Code Forum, November 29, 2001)

Q. Does the condensate line on a 90-percent gas furnace need to be heat taped? Background: The manufacturer states in the instructions "should be heat-taped to prevent winter freeze-up." The manufacturer says that freeze-up pertains to what is inside the furnace, not what is attached to the outside. What happens to the heat tape and PVC when nothing is flowing through it? And how do you heat-tape vinyl tubing on condensate pumps? Manufacturers have told me we don't need it in Oregon because when the system is gravity or pumped-drain, no water stays in the condensate line. What do we do?

A. The code does not address this issue, so contractors should follow manufacturer's installation instructions.
(Tri-County Code Forum, May 30, 2002)

Q. Regarding condensate pumps - would it be possible to use the low point drain in the foundation wall for an approved drain location for an a/c or a furnace drain?
A. No. (Tri-County Mechanical Code Forum, September, 2004)

Q. Are p-traps required on condensate drains for residential split-system evaporator coils?
A. The codes (ORSC or OMSC) have no require-ment for p-traps in condensate lines. Condensate lines should be installed according to appliance manufacturer’s installation instructions. (Tri-County Mechanical Code Forum, March 2005)

Connectors
Q. Section G2421.1.2, in the ORSC states: “connectors shall not be concealed within, or extended through, walls, floors, partitions, ceilings or appliance housings.” Sometimes we find gas range connectors passing through cabinet walls. Are cabinet walls considered partitions?
A. No, a partition is an interior wall used for dividing rooms from each other or separating different parts of a building. (Tri-County Mechanical Code Forum, March 2005)

Decorative appliance installation

Q Must the shut-off valve be accessible? I recently inspected a decorative appliance that required me to unscrew the glass face and remove the ceramic logs in order to access the shut-off valve. The contractor told me that this installation was accepted in other jurisdictions. Is this true?
A The location of and access to this valve shouldn’t have been approved by any jurisdiction. The code requires that each appliance be provided with a shutoff valve separate from the appliance. Dismantling the appliance to access the valve does not meet the intent of the code.

Definitions
Q. Please give the definition of the words "should" and "shall" as they pertain to installation instructions for furnace installs.

Example: The manufacturers' installation instructions states that the condensate drain "should" be installed with provisions to prevent winter freeze up.
(Tri-County Code Forum, December 3, 2003)

A. "Should" is a recommendation from the manufacturer. "Shall" is used in laws, regulations, or directives to express what is mandatory.
(Tri-County Code Forum, December 3, 2003)

Dryers
Q. Can you terminate a domestic clothes dryer exhaust (not a vent) through a roof?

A. Yes, such a termination would be required to follow Section 1801 in the Dwelling Code and Section 504 in the Mechanical Specialty Code. Both codes require an approved back draft damper, with no screen at the duct termination. The transition duct connection at the wall, behind the dryer, could be used as the clean out required in Section 504.3.
(Tri-County Mechanical Code Forum, November 29, 2001)

Economizers
Q. According to OSSC, Chapter 13, Energy Conservation, effective 4/1/04, under what circumstances are economizers required on HVAC systems such as simple systems, complex systems, package systems, central systems, and split systems?
A. Because energy provisions are found in the Oregon Structural Specialty Code, and since no one at the meeting had the appropriate code books, this question could not be answered. This subject may be best addressed at the structural code forum. Anyone wanting to view these provisions without buying the structural code book, can visit the Oregon Department of Energy web site at: http://www.energy.state.or.us/code/ccm/2003_Ch23-eff040104.pdf . Information on the site concerning economizers can be found on pages 140.13 through 140.20. (Tri-County Mechanical Code Forum, September, 2004)

Exhaust ducts
Q. In a recent plan review, the plan's examiner noted that we had combined the restroom exhaust with the lunchroom exhaust and her comments noted that they needed to be separate ducts per the 2002 OMSC, Section 501.2. (The 2004 edition of the OMSC has deleted this section.) I reviewed the International Mechanical Code Commentary book and it isn't clear. We have combined general exhaust with restroom exhaust for years and this is the first time it has been a problem. Please clarify.
A. Since the current code is silent on this issue, the manufacturers installation instructions should be followed. In lieu of explicit language in the manufacturers installation instructions, contacting the manufacturer’s technical staff for verification of a particular installation would be appropriate. The length and configuration of an exhaust fan duct can greatly change the output rating (CFM) and effectiveness of the fan. Therefore, when a questionable installation is encountered, performance testing may be necessary to verify the minimum CFM is being exhausted in all affected areas. As an alternate to performance testing, an engineered design could be provided, or a multi-port exhaust fan specifically designed for multiple inlet locations would be acceptable.The connection to the lunchroom exhaust could be somewhat problematic, especially if the lunchroom exhaust fan is being used as a means of occupancy ventilation, as required by Chapter 4 of the OMSC. The connection of the two systems should be methodically designed to ensure adequate ventilation is provided for the lunchroom area and that no back-drafting from the bathroom areas can occur. At the very least, performance testing is necessary to verify the minimum required CFM is being achieved in all affected areas. (Tri-County Mechanical Code Forum, September, 2004)

Exhaust fans

Q ORSC, Section M1506.4 requires exhaust fans to be vented directly to the outside. Can the vent terminate at a bird block or does it have to have its own vent through the roof?
A Yes, it may terminate at a bird block, but the vent pipe must be extended to the exterior of the building and shall terminate past the bird block to the very outside of the building envelope, with some sort of positive connection (or boot) to prevent the moist air from easily re-entering the attic. Just “getting close” for this type of application is not acceptable.

Exhaust systems-make-up air
Q. The Dwelling Code, Section G2407.7.1 requires make-up air for individual exhaust systems which exceed 350 cfm. This section gives very little direction on how to provide this make-up air or how to verify the proper amount has been provided. With some of the newer high cfm kitchen hoods, there is a need for consistency. Can you give some guidance on these two issues?
A. The dwelling code only requires make-up air for those exhaust systems exceeding 350 cfm in dwellings that contain combustion appliances, equipment or fireplaces not equipped with forced or induced draft or when equipment is not separated from the habitable area. (Exceptions to this analysis would be Section M1904(4), which deals with kilns and Section M1905.4, which deals with dryer exhaust venting.) (Tri-County Mechanical Code Forum, September, 2004)

If the habitable area of the dwelling unit doesn’t contain equipment or appliances as mentioned above, theoretically no make-up air is required no matter how large the kitchen hood is. This is a bit of a conundrum, since you’ll probably have trouble opening and closing exterior doors to the dwelling when the fan is running. But technically, Section G2407.7.1 only addresses the adverse affect depressurization will have on fuel-burning appliances and their back-drafting potential.

The code requires that “…make-up air of sufficient quantity to equal that being exhausted shall be supplied to the area being ventilated.” Make-up air can be provide in several ways, by gravity or by mechanical means. The logical choice is to bring air directly into the kitchen, although bringing air into an adjacent living area, open to the kitchen, also works. Supplying it through soffits or in the toe kick area beneath the cabinetry, right next to the stove, is a good choice.

But there are other places to introduce the air, depending on the configuration of the house and the owner's preferences. Another option might be to use an inline fan and force the air into the return air plenum of the furnace, this would allow the potential for tempering and filtration during colder months. (this option will probably be limited to smaller exhaust systems) Still another way might be to provide tempered make-up air is by using an inline duct heater. This heater could kick in when incoming air is below a set temperature. (typically 500F is a good starting point).

Additionally, when using one of the mechanical means to provide make-up air, the make-up air system must work whenever the kitchen exhaust is running. This can be accomplished by inter-connection of the make-up air fan and the kitchen hood fan. If the kitchen fan has multiple settings, the makeup air system may also need multiple settings.

People who are familiar with home diagnostics recognize the benefits of worst-case depressurization testing and the current ORSC provides an acceptable procedure, outlined in Appendix D, Recommended Procedure for Safety Inspection of Existing Appliance Installation, item 7, for the verification of the combustion air needs (see Section M1701.2). (Tri-County Mechanical Code Forum, September, 2004)

Furnace-as construction heater
Q. Most manufacturers state clearly in their installation instructions: “WARNING: Do not use this furnace as a construction heater. Use of this furnace as construction heater exposes the furnace to abnormal conditions, contaminated combustion air and lack of air filters. Failure to follow this warning can lead to premature furnace failure and /or vent failure which could result in a fire hazard and/or bodily harm." Are there jurisdictional parameters?
A. No. This is not a code issue. (Tri-County Mechanical Code Forum, September, 2004)

Furnaces
Q. Condensate for a furnace - can you terminate outside?

A. Yes, condensate drains can terminate outside, provided that for example, the condensate would not freeze on a sidewalk or other walk way.
(Tri-County Mechanical Code Forum November 29, 2001)

Q. Can we provide combustion air to the furnace through the return air ductwork?

A. Yes, the Dwelling Code, Section 2004.2 allows for "Ducts admitting outdoor air may be connected to the return air side of the heating system." The Mechanical Specialty Code does not have the same verbiage found in the Dwelling Code, which allows for the connection to the return air duct. All of the requirements found in the Dwelling Code, Section 2004.2, except for the last sentence, can be found in the Mechanical Specialty Code, Section 706.1.1. As an alternate to the requirements found in Section 706, Section 707 of the Mechanical Specialty Code allows the use of a "mechanical forced-air system" to be used to provide combustion air through the buildings mechanical ventilation system.
(Tri-County Mechanical Code Forum, November 29, 2001)

Q. Insulating the vent of a 90+ furnace within unconditioned spaces - We have worked in jurisdictions that do not require this. Recently, in two jurisdictions, we have learned (after installation of the furnace) that they require insulation. Even those jurisdictions have different requirements for the insulation. Shouldn't all Tri-County jurisdictions be consistent on this?

A. There is no code requirement for the insulation of the vent for a 90%-plus furnace. The code requires that you follow the manufacturer's installation instructions. See Dwelling Code, Section 1307.1, and See Mechanical Specialty Code, Section 304.1.
(Tri-County Mechanical Code Forum, November 29, 2001)

Gas valves
Q. Is the required gas-shut-off valve for a gas insert (decorative appliance) allowed to be in the cavity between the base and/or sides of the insert and the masonry walls of the original fireplace?

A. Yes. The valve shall be accessible. "Accessible" is defined as having access that requires the removal of an access panel or similar removable obstruction. Refer to the Dwelling Code, Sections 1202, 2606.3 and 2606.3.2
(Tri-County Code Forum, May 30, 2002)

Q. Do we have to replace the old style gas cock, when changing-out a furnace or adding a new appliance?

A. There is no code requirement to replace the existing gas valve. Refer to Section M102.4.
(Tri-County Code Forum, December 3, 2003

Q. Do you need red, yellow or blue handles on a gas valve?

A. There is no code requirement to use colored handles on gas valves.
(Tri-County Code Forum, December 3, 2003

Gas shut-off valves
Q. Section G2419 Gas Shutoff valves: Can a gas meter shut-off valve be the piping system shut- off, or does the code require both?

A. The "meter valve" addressed in Section G2419.2 is the utility suppliers valve and can not be used as a substitution for the other valves required in Sections G2419.3, G2419.4 and G2419.5. The code does not require a generic "piping system shut-off" on the house side of the meter, except for the "common system" identified in Section G2419.3.
(Tri-County Code Forum, December 3, 2003)

Q. Where would a typical piping shut-off be located?

A. The Dwelling Specialty Code, Section G2419.3 requires a shut off valve be installed outdoors at each building, in a common system serving more than one building. Section G2419.4 requires a listed shutoff valve be installed immediately ahead of each MP regulator and Section G2419.5 requires each appliance be provided with a shutoff valve.
(Tri-County Code Forum, December 3, 2003)

Gas Venting
Q. Screws in venting: Are they necessary? For example, in type B venting.

A. No. Manufacturers instructions for B-vent typically allow, but do not require the use of screws, provided the screws do not exceed ¼ inch in length and do not penetrate the inner wall of the vent.
(August 9, 2001 Tri-County Code Forum)

Q. When changing out a furnace or water heater, is it necessary to change the vent connector from 3 to 4 inches?

A. Maybe. You must change the vent connector when required by the listing of the appliance. When using a plumbing minor label to replace an existing water heater, a mechanical permit would not be necessary to change out a short section of the water heater connector. If the vent is being changed or modified or a liner is being installed, a mechanical permit would be required.
(Tri-County Code Forum, February 28, 2002)

Horizontal clearance from air inlet

Q OMSC, Section 401.5.1, 804.3.4(4) and C503.8(2) appear to have conflicting requirements for the horizontal clearance from an air inlet. Which section prevails?
A Section 401.5.1 has a general requirement of 10 feet for horizontal clearance and further states: “… except as otherwise specified in this code.” Sections 804.3.4(4) and C503.8(2) have specific requirements that override the general requirements found in Section 401.5.1.

HVAC Unit Change Outs
Q. Some jurisdictions require structural calculations for a direct change out. In 95 percent of change outs, the old unit's weight is substantially heavier than the new unit. This adds $500 - $700 in costs to the building owner. What is the prevailing requirement in Tri-County jurisdictions?

A. The code does not directly address a change out situation. If the new equipment weighs more than the existing unit, then structural calculations are required. If the new equipment exceeds 400 pounds, the method of attachment must be shown on the plans. See OSSC, Volume 2, Chapter 16, Division IV, Section 1632.1.
(Tri-County Mechanical Code Forum, November 29, 2001)

Inspections
Q. It has been confusing over the past several years as to who is responsible for inspecting the underground pipeline from the LPG tank to the house.

A. The local jurisdiction's one- and two-family mechanical inspector. (August 9, 2001 Tri-County Code Forum)

Q. At what physical point does a one-and two-family mechanical inspector start his/her inspection?

A. After the first stage regulator, which is normally located at the tank. (August 9, 2001 Tri-County Code Forum)

Q. Is an underground LPG gas line required to be inspected and tested before it is covered?

A. Yes. (August 9, 2001 Tri-County Code Forum)

Q. If the gas piping is installed, has an air test in place and all appliances are installed and vented etc., it stands to reason that the inspector can reasonably inspect the installation. Assuming no corrections, is it necessary for a residential mechanical inspector to go back after the meter is set, to observe the equipment, the furnace or other mechanical equipment actually working?

A. No. Exception: Inspection of equipment required to be electrically interlocked to an appliance such as motorized dampers installed in combustion air openings or power venters that are not an integral part of an appliance. (August 9, 2001 Tri-County Code Forum)

Q. What if there are corrections, even after the meter is set?

A. It's the contractor's responsibility to call for a re-inspection. (August 9, 2001 Tri-County Code Forum

Q. Is it standard practice in Tri-County jurisdictions to return to the site only when corrections are necessary?

A. Yes, in which case the contractor shall call for re-inspection. (August 9, 2001 Tri-County Code Forum

Q. What if there are multiple contractors and sub-contractors working on the job. Will there be one inspection called, or multiple tests?

A. Contractors and sub-contractors must pull a permit for the portion of the gas line installed by them and for each installation, and the one- and two-family mechanical inspector must follow up by inspecting each contractor's portion.
(August 9, 2001 Tri-County Code Forum)

Q. In those jurisdictions that do not participate in NW Natural's Gas Express program, do you make a trip first for the gas piping pressure test, then a second trip to inspect the installation after connection and then possibly a third trip when corrections are necessary?

A. Yes.
(August 9, 2001 Tri-County Code Forum)

Q. Sometimes there are multiple permits for one job. When one permit is phoned in for an inspection, the inspectors take out all the permits and perform inspections on permits for which no inspection was requested in addition to the one which was requested. Staff is concerned that the other permits will not be inspected and that the contractor will cover the work. Is this appropriate? Should not all permits be phoned in separately for inspection?

A. No, it is not appropriate for inspectors to perform inspections on permits for which no inspection was requested. Yes, all permits should be phoned in separately for inspection; it is not up to the inspector to determine when the work is done; this is the responsibility of the contractor. When a contractor covers work that should be inspected it is a compliance issue that should be dealt with separately.
(June 19 Tri-County Electrical Code Forum)

Insulation
Q. Insulation on ductwork in a residence: When running flex duct (i.e., Y's, boots, T's, or short pieces of hard pipe) Does the insulation have to be foil back or have any kind of vapor barrier?

A. The Dwelling Specialty Code (ODSC) does not require duct insulation to be foil back or to have any kind of vapor barrier when installed in unconditioned spaces. Proof that the duct insulation meets the R-8 requirement may be required. OSSC, Section 1308.1.1 requires a vapor barrier to be installed on supply and return ducts in spaces which are vented to the outside. Additionally the OSSC, Division III (Other buildings), Section 1317.7 requires duct- work conveying both heated and cooled air that is outside the insulated building envelope to have a vapor barrier having a perm rating not exceeding .05 perm. The requirements found in the OSSC cover all work not regulated by the ODSC.
(Tri-County Code Forum, April 22, 2004).

Q. When bidding a retrofit job to insulate existing ductwork, can raw insulation be used?

A. Yes. Fiberglass blankets are commonly used for this purpose.
(Tri-County Code Forum, April 22, 2004)

LPG Licensing
Q. Does the state require any license to install LPG systems?

A. Yes, a LPG installer license from the State Fire Marshal's Office is required. (August 9, 2001 Tri-County Code Forum)

Q. If I'm a homeowner and want to install my own LPG piping, do I need to be licensed?

A. Yes, you must be a licensed LPG installer. The only exception to the licensed LPG installer requirement is a journeyman plumber or a journeyman plumber may install LPG gas piping. (August 9, 2001 Tri-County Code Forum)

LPG Location
Q. Is a LPG furnace allowed in a basement, pit or crawl space of a home?

LPG Systems

A. Yes, unless prohibited by the listing of the furnace. (August 9, 2001 Tri-County Code Forum)

Q Where does the enforcement of LPG systems start for mechanical inspectors?
A Mechanical inspections begin at the first-stage regulator, which is normally located at the tank. The tank and any associated piping to the first-stage regulator are under the jurisdiction of the Office of the State Fire Marshal (or under an exempt fire district).

LPG Testing
Q. What is the appropriate test pressure when testing LPG piping systems in a one- and two-family dwelling?

A. If the house piping is on the low side of the second stage regulator, the test would be 10 PSI for 15 minutes. A building official could approve an alternative method if requested by the contractor. NFPA 54 allows 1½ times the working pressure, but no less than 3 pounds, and is an acceptable alternate. Air pressure testing at the reduced pressures allowed by NFPA 54 requires the use of a manometer or similar testing devise with comparable accuracy. OMSC has the same requirements as found in the Dwelling Code and allows the use of NFPA 54 in the exception. (The requirement stated above for the OMSC is a new amendment, which goes into effect Oct. 1, 2001) (August 9, 2001 Tri-County Code Forum)

Q. In one- and two family dwellings, is the outside piping tested to the same test pressures as the inside piping?

A. The code allows different testing pressures and duration of test, depending on the water column or working pressure in the line. The working pressure is usually higher between the first and second stage regulators and lower after the second stage regulator. The test on the low side is 10 PSI for 15 minutes below 14 inches of water column. The test on the high side is 60 PSI for 30 minutes. See Section 2603.3.1 in the Dwelling Code . (August 9, 2001 Tri-County Code Forum)

Q. In commercial/industrial structures, is the outside piping tested to the same test pressures as the inside piping?

A. See above answer. (August 9, 2001 Tri-County Code Forum)

Manufactured Homes
Q. Does a replacement furnace in a manufactured home have to be listed for installation in manufactured homes?

A. No. Refer to the State of Oregon Manufactured Dwelling and Park Specialty Code. Chapter 6, Section 6-3.5 states in part;
(b) Furnaces installed in a manufactured dwelling after the completion of the initial sales contract shall be listed but do not have to be listed for manufactured home or mobile home use;
(c) Fuel-burning furnaces shall be installed to provide for the complete separation of the combustion system from the interior atmosphere of the manufactured dwelling by:
The installation of a listed direct vent (sealed combustion system) appliance; or
The installation of the appliance within an enclosure accessible only from outside the manufactured dwelling so as to separate the appliance combustion and venting systems from the interior atmosphere of the manufactured dwelling. There shall not be any door, removable access panel, or other opening into the enclosure from the inside of the manufactured dwelling. Any openings or penetrations for ducts return air inlets, piping or wiring shall be sealed with noncombustible caulking or equal.
(Tri-County Code Forum, February 28, 2002)

Mechanical Minor Labels
Q. Will there be a mechanical minor label program that could be used in simple change outs?
A. Yes and no. Oregon allows local jurisdictions to develop commercial and industrial mechanical minor label programs under OAR 918-100-0020, but does not mandate them. Portland has such a program, but not all tri-county jurisdictions do. The 2003 legislature passed HB 714 — allowing the state to administer mechanical minor labels. A state goal is to draft and adopt rules this year. (Tri-County Mechanical Code Forum, March 2005)

MP regulators
Q. Are MP regulators included in the definition of appliances? ORSC, Section G2403, defines an appliance as any apparatus or equipment that utilizes gas as a fuel or raw material to produce light, heat, power, refrigeration, or air conditioning.
A. No, MP regulators are not considered appliances. (Tri-County Mechanical Code Forum, March 2005)

MP regulators-shut off valves
Q. Section G2419.4 requires that a listed shutoff valve be installed immediately ahead of each MP regulator. Section G2419.1.3 requires shutoff valves to be located so as to provide access for operation and be installed so as to be protected from damage. What access should be provided for MP regulators?
A. Access is defined as “that which enables a device, appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction.” Section G2419.4, requires MP regulators to have the same access. (Tri-County Mechanical Code Forum, March 2005)

Oil Tanks
Q. Section 2701.2 of the One- and Two-Family Dwelling Specialty Code requires that above-ground oil tanks have rigid noncombustible supports to prevent tanks from settling or shifting. The code further requires that residential tanks installed outside the dwellings must be a minimum of five feet from the property line and be protected from weather and physical damage. They may be at surface level or elevated. Tanks may hold no more than 660 gallons; the average residential tank is 275 gallons. An informal survey of several tri-county jurisdictions shows inconsistent application of installation requirements,leading to complaints from the industry. What should jurisdictions require?

A. In lieu of engineered plans from tank manufacturers, the following prescriptive guidelines shall apply:

1. 275-gallon or smaller oval tanks ,located outside, aboveground. Bottom of tank 12 inches or less above slab:

a. Size: 275 gallons or less.
b. Distance from property line: Minimum five feet.
c. Support: Installer must submit a design showing concrete-slab thickness, concrete re-enforcing, tank-stand attachment, and slab's proximity to house.
d. Seismic strapping: Design required.
e. Protection from weather: Tank must be painted.
f. Protection from physical damage: Barrier post required if installed in the normal path of vehicles.
g. Permits: Required.

2. 275 gallon or smaller oval tank in a basement or garage, with tank bottom 12 inches or less above slab:

a. Size: 275 or 220gallons.
b. Distance from property line: Not applicable.
c. Support: Existing concrete slab. Install tank per Figure #2701.
d. Seismic strapping: Attach tank per Figure #2701.
e. Protection from weather: Not applicable.
f. Protection from physical damage: Barrier post required if installed in the normal path of vehicles.
g. Permits: Required.

3. Tanks 300 to 660 gallons, inside or outside, above ground:

a. Size: 300- 660 gallons.
b. Distance from property line: Minimum 5 feet. (Does not apply to interior installations.)
c. Support: Design required.
d. Seismic strapping: Design required.
e. Protection from weather: Tank must be painted when exposed to outside environment.
f. Protection from physical damage: Barrier post required if installed in the normal path of vehicles.
g. Permits: Required .

Illustration

Permits
Q. When is a mechanical permit required for the repair or replacement of a gas or oil furnace not exceeding 20 amps or an electrical furnace or air conditioning unit or refrigeration unit?
Problem: An LHR contractor was under the impression that the only permit needed to do a push/pull on a like-for-like electric furnace was an electrical minor label. A local mechanical inspector informed him that a mechanical permit was also required. He has questioned the need for the mechanical permit and has asked for clarification of this issue.
A. Electrical minor labels are for certain electrical work only and do not cover mechanical or plumbing. The installation of a furnace is a mechanical installation and requires a mechanical permit. (Tri-County Mechanical Code Forum, March 2005)

Permitting Requirements for Exhaust Fans
Q. One and Two Family Dwelling: Are mechanical permits required for exhaust fans for radon or for exhaust fans providing alternate means of ventilating an attic or underfloor space?

A. Yes.
(August 9, 2001 Tri-County Code Forum)

Q. One and Two Family Dwelling: Are mechanical permits required for exhaust fans voluntarily installed to provide supplemental attic or underfloor ventilation?

A. Yes.
(August 9, 2001 Tri-County Code Forum)

Q. Are mechanical permits required for "Whole house" exhaust fans, typically located in the hallway ceiling of the upper story ?

A. Yes. (August 9, 2001 Tri-County Code Forum)

Piping systems
Q. Are Rigid ProPress G- fittings with HNBR yellow O-ring seals recognized for use for natural gas and copper LP gas piping systems? Is the exterior penetration to the meter or regulator required to be rigid iron pipe?
A. The answer to the first question is no, these fittings are not identified in the code and have not been approved for gas piping installations. Sections R104.11 (in the ORSC) and 105.2 (in the Oregon Mechanical Specialty Code) allow building officials to approve alternate materials for use in their jurisdictions. (Tri-County Mechanical Code Forum, March 2005)

Question 2 concerns the penetration of gas piping at the exterior of the building for connection to the meter set. Neither the ORSC nor OMSC identify a specific material or method of installation for this location. The materials should be adequate to withstand the pressures and tension that may be placed on them from the serving utilities when setting the meter, to prevent damage to the piping system inside the building. NW Natural prefers that the exterior penetrations at the meter or regulator be made of rigid iron pipe, securely fastened and supported, to prevent rotation in the wall cavity. Although the code does not prohibit other materials, the code panel shares the gas company’s concerns and encourages contractors to comply with its recommendation. (Tri-County Mechanical Code Forum, March 2005)

Piping under asphalt
Q. We are installing polyethylene natural gas piping that is specially engineered and certified for underground installations. The piping will be installed under an asphalt driveway. Section G2414.14.1 states "Plastic pipe shall not be used within or under any building or slab..." Is an asphalt covered driveway considered a "slab"?

A. No, the International Residential Code Commentary specifies only concrete is considered a slab.
(Tri-County Code Forum, September 17, 2003)

Piping under concrete
Q. May a piece of poly pipe installed under a sidewalk behind the right of way be installed with a conduit and venting or sleeve and venting?

A. Yes, up to a maximum of five feet in width.
(Tri-County Code Forum, September 17, 2003)

Piping-condensate lines
Q. Do copper condensate lines or return piping of heating/cooling units supported by galvanized hangers or other dissimilar metals constitute a potential for galvanic action?

A. Yes the potential is there and that is why both the ODSC and the OMSC provide general requirements for the hanging or supporting of piping systems as follows: "Pipe hangers and supports shall have sufficient strength to withstand all anticipated static and specified dynamic loading conditions associated with the intended use. Pipe hangers and supports that are in direct contact with piping shall be of approved materials that are compatible with the piping and that will not promote galvanic action." (M1309.2 and 305.2, respectively)
(Tri-County Code Forum, January 22, 2004)

Q. Do copper condensate lines or return piping of heating/cooling units that are in direct contact with galvanized sheet metal duct and/or plenum constitute a potential for galvanic action? Would the aforementioned sections of code apply, since they reference piping supports and hangers only?

A. Neither code addresses the touching of dissimilar metals as mentioned in your question. The panel recommends protecting or isolating any piping from potential corrosion or possible vibration by means of 10 mil. tape or insulation or other form of equivalent protection.
(Tri-County Code Forum, January 22, 2004)

Piping- gas fuel
Q. Is it acceptable to size gas fuel piping, using the sizing tables found in the last edition (2000 Edition) of the Oregon Dwelling Specialty Code?

A. Yes.
(Tri-County Code Forum, September 17, 2003)

Piping-hydronic
Q. Is hydronic piping defined as heating water systems?

A. Neither the Oregon Mechanical Specialty Code (OMSC) or the Oregon Dwelling Specialty Code (ODSC) define "hydronic piping". The dictionary defines "hydronic" as a system of heating or cooling that involves transfer of heat by a circulating fluid in a closed system of pipes.
(Tri-County Code Forum, September 17, 2003)

Q. Does hydronic piping need to be separated from the domestic water system via a backflow preventor?

A. Yes and No. This is a complicated subject, with many variables. The simple answer is there are two basic types of systems relating to your question. One system would be considered a "closed system" and the other type of system would be a "open system". A "closed system" would be defined as a heating system which is closed off from the environment and its heating fluid is not changed except for maintenance. A "open system" is defined as a system in which the heating fluid is replaced often. The OMSC and Chapter 21 in the ODSC pertain to and regulate "closed systems". The potable water supply requires separation and protection from the "closed system", which could be accomplished by the use of a double wall heat exchanger or a back-flow preventor. The "open system" is regulated by the Oregon Plumbing Specialty Code (OPSC).
(Tri-County Code Forum, September 17, 2003)

Q. If there is no backflow preventor and the heating system is direct connected to the domestic system, is the hydronic piping no longer hydronic piping?

A. An "open system" is still considered a hydronic piping system, but is regulated under the plumbing code, because it uses the domestic potable water as its heating medium.
(Tri-County Code Forum, September 17, 2003)

Q. Does the hydronic heating water system need to comply with the mechanical code under this piping arrangement?

A. "Closed systems" are regulated under the OMSC and the ODSC. If a system uses potable hot water for both domestic and heating purposes ("Open system"), it would be regulated under the OPSC.
(Tri-County Code Forum, September 17, 2003)

Piping - refrigerant
Q. Section 1108 refers to a required refrigerant piping pressure test for refrigeration systems. Is this test required on both commercial refrigeration units and air conditioning, or just refrigeration units (walk-in coolers, cold warehouses and the like)."

A. Yes, each refrigerant-containing part of every system that is erected on the premises, except compressors, condensers, vessels, evaporators, safety devices, pressure gauges and control mechanisms that are listed and factory tested, shall be tested and proved tight after complete installation, and before operation.
(Tri-County Code Forum, September 17, 2003)

Range Hoods
Q. Is a hood required for domestic ranges (one and two family)?

A. No, in the one and two family dwelling code, a hood is not required for domestic ranges unless the cooking appliance listing requires it. Domestic open-top broilers require a ventilating hood installed as required in Section 1804 of this code.
(August 9, 2001 Tri-County Code Forum)

Refrigeration brazing

Q What is the requirement for certifications regarding refrigeration brazing? For example, is a certification from ORACCA accepted?
A Under the Oregon Mechanical Specialty Code (OAR 918-440-0015), all persons engaged in brazing or welding related to the installation, alteration, or repair of refrigeration piping systems must have a current valid certification issued upon completion of a class given by a division-approved organization. (There are five such organizations: Oregon Air-Conditioning Contractors Association (ORACCA), Linn Benton Community College, Local 16- Sheet-Metal Training Center, JC and Associates and Local 701- International Union of Operating Engineers.) Refrigeration systems installed in dwelling units regulated under the Oregon Residential Specialty Code are exempt from this requirement. Under the Oregon Boiler and Pressure Vessel Program, the requirements of OAR 918-225-0430(5) shall be enforced for all welded, brazed, or mechanically assembled refrigerant piping exceeding two inches NPS containing any refrigerant chemical other than A-1 or B-1 refrigerants, as listed in ASHRAE 34. Persons performing these duties must have a Class 5-B Refrigeration Piping Mechanic Certification, as required by OAR 918-225-0691.

For more information about division-approved groups, contact Mike Ewert, (503) 373-7529, or send e-mail to mike.d.ewert@state.or.us.

Return-air plenum insulation
Q. Does a return-air ceiling plenum require R-8 insulation at an exterior wall?
A. Yes. This question applies only to structures classified as townhouse, row houses, and apartment complexes and structures regulated by the Oregon Structural Specialty Code and related provisions in the OMSC; using wall or ceiling cavities as plenums is not allowed in one- and two-family dwellings. If the cavity to be used as a plenum extends to the exterior walls of the building, energy-envelope provisions in Chapter 11 of the ORSC and Chapter 13 of the OSSC apply. (Tri-County Mechanical Code Forum, March 2005)

Sealants
Q. Can silicone sealant be used to seal the joints in a duct system?

A. Yes, if listed for that use.
(Tri-County Code Forum, November 15, 2002)

Sealing duct joints
Q. Several code changes were submitted to the Oregon Dwelling Specialty Code to correct conflicting or erroneous language which has a direct impact on the HVAC industry. One of these code changes cleans up the conflict in Section M1601.3.1 dealing with sealing of duct joints. With widespread support of the HVAC industry and many hours of discussion between the state, local jurisdictions, suppliers and installers, would it be acceptable for jurisdictions to implement this change early by the use of Section R104.11 "Alternative materials, design and methods of construction equipment"?

A. The code change to Section M1601.3.1 clarifies the underlining intent behind the original code language, submitted by the Office of Energy, and is inline with real world application and the installation instructions provided by the product manufacturer. Although this code change modifies the original code language slightly, it will provide the end results desired by the Office of Energy. Therefore an alternative material or method for duct sealing may be approved when the building official finds that the proposed material or method offered complies with the intent of the provisions of this code.
(Tri-County Code Forum, September 17, 2003)

Shut-off valves-location
Q. Does the exception found in Section G2420.5 pertaining to the location of shut-off valves for decorative appliances apply to room heaters also?
A. Yes, the appliance must be listed to both standards. The appropriate standard for vented room heaters is ANSI Z21.11.1, and ANSI Z21.60 for Decorative Gas Appliances For Installation In A Vented Fireplace. (Tri-County Mechanical Code Forum, March 2005)

Smoke detectors
Q. Section 606.2.1 of the Oregon Mechanical Specialty Code, states in part; "……….smoke detectors shall be installed in the return air duct or plenum upstream of any filter, exhaust air connection, outdoor air connection, or decontamination equipment………." Some return air grills are designed with a changeable fabric filter for easy maintenance. Does Section 606.2.1 apply to these filters? If it does where would we install the smoke detector?

A. No, this code section would not apply to a filter located at the return air grill.
(Tri-County Code Forum, December 3, 2003)

Q. Section 606.4.1#2 requires a duct smoke detector to activate a visible and audible signal at an approved location. The installation is a push-pull in an existing commercial building that did not have any signal prior. The building does not have a fire alarm system. Would such an installation require a visible and audible signal installed?

A. No, the change out of an existing unit would not trigger bringing the entire mechanical system up to current code. Section 102.4 in the Oregon Mechanical Specialty Code states; "Additions, alterations, renovations or repairs to a mechanical system shall conform to that required for a new mechanical system without requiring the existing mechanical system to comply with all of the requirements of this code. Additions, alterations or repairs shall not cause an existing mechanical system to become unsafe, hazardous or overloaded.
Minor additions, alterations, renovations and repairs to existing mechanical systems shall meet the provisions for new construction, unless such work is done in the same manner and arrangement as was in the existing system, is not hazardous and is approved."
(Tri-County Code Forum, December 3, 2003)

Tape/Approved or mastic
Q. Unlisted duct tape has been installed on the metal to metal and flex to metal air duct joints of a furnace installation in a single-family dwelling. Is it required that the unlisted duct tape be removed before installing the approved tape or mastic?

A. No, approved tape may be installed over unlisted duct tape.
(Tri-County Code Forum, September 17, 2003)

Q. If the unlisted tape remains, is it acceptable to apply the approved tape directly over the unlisted tape? Is there a minimum lap required?

A. Yes. ½ inch overlap is acceptable.
(Tri-County Code Forum, September 17, 2003)

Tape/metal
Q. Where metal tape with butyl rubber adhesive, listed to UL 181B-FX, is used to seal S-lock and drive clips at metal duct connections, is there a minimum lap required beyond the joint or seam?

A. Yes, ½ inch.
(Tri-County Code Forum, September 17, 2003)

Vapor Barriers in Supply Ducts
Q. Recently, an inspector required me to install a vapor barrier on the supply ducts, which were installed in an unconditioned space. I can't find this requirement in the 2000 Edition of the Dwelling Code and the inspector couldn't find the specific code section either. Can you point me in the right direction?

A. A vapor barrier is not required on the supply ducts in unconditioned spaces.
(August 9, 2001 Tri-County Code Forum)

Ventilation-Repair Garages
Q. I have a question about the IMC Section 502.11 dealing with repair garages when a motor vehicle is in the garage. The group occupancy for this building is Group H division 4. In addition to the ventilation requirements for the occupants of the building, the code says that each engine repair stall shall be equipped with an exhaust pipe extension duct. What does the duct need to be made of? Nothing in the code gives requirements.

A. PVC pipe is most widely used and probably the best choice for underground systems, due to corrosion from both inside and outside elements that may deteriorate the piping system. Neither the OSSC nor the OMSC consider the tail pipe extension (duct or "Source Capture System") and the products conveyed in the extension duct to be of such a hazard to warrant specific product or installation requirements; therefore the manufacturer's installation instructions, along with the specific design requirement found in OSSC, for a minimum of 300cfm are adequate and appropriate to regulate "Vehicle Exhaust Evacuation System" or "Source Capture System" over 10 feet in length. The installation instructions provided by two manufacturers of "Vehicle Exhaust Evacuation System" recommend the use of PVC, fiberglass or stainless steel duct material for underground installation, when used in conjunction with their products. Since no specific requirements can be found in either the OSSC or OMSC and there is no apparent national standard regarding installation of "Vehicle Exhaust Evacuation Systems," the design provided by the installing company and installation instructions provided by the manufacturer should be followed.
(Tri-County Mechanical Code Forum, November 29, 2001)

Venting
Q. When PVC is used for venting a condensing furnace or water heater, what is required to protect the pipe from metal plumber's tape used for hangers or penetrations of the exterior concrete wall?

A. Tape suitable to protect from abrasion, such as 10-mil tape, is acceptable.
(Tri-County Code Forum, May 30, 2002)

Venting-bath fan materials
Q. What materials are acceptable for bath fan venting under the Oregon Mechanical Specialty Code?

A. The OMSC, Section 501.5 states the same thing as Section M1501.1 of the ODSC. For the most part, then, the same provisions stated in question 1 would apply. Furthermore, OMSC has provisions for the penetration of fire-rated assemblies and those provisions are found in Section 603.5.5 and 603.6 and must be observed when applicable.
(Tri-County Code Forum, January 22, 2004)

Water Heaters
Q. Regarding on-demand tankless gas or liquefied-petroleum water heaters: Some of the new units on the market require us to supply combustion air from the space in which the water heater is installed. If a unit is installed in a garage and vented to the outside, do I need 50 cubic feet of combustion air for each 1,000 Btu's for space- heating and hot-water heating in a single-car garage? In a double-car garage?

A. Yes. If the garage does not meet that requirement, an additional supply of combustion air is necessary.
(Tri-County Code Forum, May 30, 2002)

Q. Some of these units modulate up to 117,000 Btu's and some up to 235,000 Btu's. The smallest I could find for a house is 117,000 Btu's . If this unit is considered power-vented or needs to have the vent joints sealed with a high-temperature sealant, can we use a B-vent? If not, can we put B-vent around the vent pipe for reduced clearance?

A. The venting system must be installed according to its manufacturer's installation requirements. The committee discussed liability for using a product in a manner other than that intended by the manufacturer. The code does not have guidelines for using B-vent as a sleeve. The committee suggested enlisting the manufacturers of the tankless water heaters and/or B-vent to find a solution.
(Tri-County Code Forum, May 30, 2002)

Q. When installing a gas water heater, must you have a B-vent?

A. This question is rather open-ended and the scope of the question is undefined. Since the question does not specify the parameters of the installation, the committee focused on unconditioned spaces and replacement issues.

If an existing gas water heater is replaced with a new gas water heater, refer to Section 117.2. and the BCD staff interpretation memo addressing this issue. Double wall type-B gas venting material is commonly used in unconditioned spaces for new installations. For existing changeouts, Section 117.2 states; "Replacement of an existing water heater shall not require the existing plumbing, mechanical or electrical systems to comply with provisions of this code for new construction, provided the installation complies with the listing requirements of the appliance." Typically unconditioned spaces include attics, crawl spaces, and garages. The requirements for using B-vent as a connector in unconditioned spaces has been around for a number of years.
(Tri-County Code Forum, February 28, 2002)

Q. What is meant by "Like for like"?

A. The term "like for like" is not defined or used in the code. When referring to the replacement of an existing water heater, the new water heater shall be of the same type (electric to electric, gas to gas, oil to oil, etc.), input rating similar, fuel efficiency similar, and water volume similar, etc.

Section 2101.3 specifically addresses the removal, installation, or replacement of gas appliances. Section 2101.3.1 requires resizing of the chimney or vent system at the time of removal, installation, or replacement of gas appliances. Improper vent sizing not only can result in significant chimney and vent deterioration, but also can result in spillage of products of combustion within the structure. Spillage of products of combustion would usually be normally considered dangerous to life and if so, would not be covered by the exceptions in Section 117.2.
(Tri-County Code Forum, February 28, 2002)

Q. What about "Like for not like"?

Discussion:
"Like for not like." For the replacement of a gas water heater that is not of the same type, input rating, or fuel efficiency, refer to the GAMA venting tables. The same code sections addressed above would apply.
(Tri-County Code Forum, February 28, 2002)

Waterheaters-permitting
Q When a water heater is changed out from electric to gas, is a mechanical permit required? If so, is a mechanical permit pulled separately, as the plumbing is usually done under a minor label?

A Yes, a separate mechanical permit is required in addition to the plumbing minor label.
(Tri-County Code Forum, April 22, 2004)

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