The Air Conditioning Contractors of America (ACCA) hereby appeals to the IAPMO Standards Council regarding the results of the UMC TC’s recent ballot of Item # 072, Association Action Ballots – 2018 UMC. ACCA strongly urges the Standards Council to retain the current exception for residential occupancies found under paragraph 603.4.1 in the 2015 UMC for the pending 2018 edition. Item #072 proposes to amend 603.4.1 by deleting the current exception for residential occupancies. This would place a limit on the use of flex duct in residential homes to installations not exceeding five (5) feet in length. ACCA opposes the adoption of such a limitation in residential dwellings. At its May 2017 meeting, the UMC TC reviewed comments by ACCA (and others) opposing the proposed revision to delete the above exception. ACCA pointed out that the supporting documentation associated with this proposal did not contain any field data supporting this limitation in residential applications. After much discussion, the TC voted to retain the exception as shown in the 2015 edition. Friction loss/pressure loss and duct leakage can be common problems associated with any duct system which is why proper system design and field installation must occur to minimize such losses and maximize energy efficiency. If the duct system is properly sized in accordance with ACCA Manual D, Residential Duct Systems, and properly installed, flexible ducts should be allowed for residences without limitations. ACCA Manual D is referenced in the 2015 edition of the UMC and continues to be a mandatory part of the 2018 edition. The argument that flex ducts should be limited in residences due to the potential for improper design and installation can be made for any type of listed appliance, equipment or component. Any listed component, appliance or system that is not properly designed or installed can perform poorly. The UMC should not be restricting anything that has been listed, designed and installed properly, regardless that there is a potential for it to be improperly used or installed in the field. This represents a potential “slippery slope” for the code. In addition, ACCA is aware that there were interests representing firefighters at last May’s UMC hearing that urged the TC to limit the use of flex duct in residences due to a few reports of instances where the support means for flex ducts in a commercial building had affected the safety of firefighters inside a fully engulfed structure. Such reports pertained to a commercial building fire and not a residence. During discussion at the meeting, it was noted that a fully engulfed residential structure could involve many other types of falling debris and that it would not be logical to single out flex duct supports from all the other types of potential debris that could impact firefighter safety.

AIR DUCT COUNCIL 1901 N. Roselle Rd. Suite 800 Schaumburg, IL 60195 847-706-6750 (T) 847-706-6751 (F) www.flexibleduct.org

The Air Duct Council (ADC) is a North American trade association representing flexible manufacturers across North America. ADC members produce over 95% of the flexible duct installed in residential and commercial buildings. ADC appeals to the IAPMO Standards Council, meeting November 15th, to consider the results of the balloting and in particular Item #072. The ADC strongly appeals to the Standards Council to maintain the current exception for residential dwellings, as currently appearing under paragraph 603.4.1 in 2015 UMC. When the UMC TC met last May to review comments received urging deletion of the present residential exception, many organizations and leading HVAC authorities stated that there is insufficient evidence, including actual field data, that would support the removal of the residential exception. The UMC TC, at that meeting voted to keep the present residential exception as it is currently appears in the 2015 UMC. The argument was put forth that flexible duct installations in residential dwellings should be limited because of faulty design and improper installation practices. This argument cannot be substantiated because all duct systems – be they flexible, sheet metal or duct board – if not properly designed or installed – can operate at an unacceptable level. The Air Duct Council, formerly the Air Diffusion Council, has for many years, published and distributed instructional literature on the proper methods for installing flexible duct to achieve maximum performance. The ADC Flexible Duct Performance & Installation Standard is an example of our members’ dedication to promote proper flexible duct use. ADC endorses and supports the language and procedures in ACCA’s Manual D. --stating that if the overall duct system is designed properly and installed properly, there should be no restriction in the codes. In conclusion, the members of the Air Duct Council, strongly urge the IAPMO Standards Council to retain the current language in the 2015 UMC and vote against amending section 603.4.1 removing the flexible duct residential exception. Respectfully submitted, Jack Lagershausen Executive Director Air Duct Council Filed: October 27, 2017

October 27, 2017 Ms. Gaby Davis Executive Vice President of Global Operations Secretary, IAPMO Standards Council IAPMO 4755 E. Philadelphia St. Ontario, CA 91761 Sent by E-mail on October 27, 2017 Subject: Uniform Mechanical Code Technical Committee Item 072 Proposed Amendment to Item 603.4.1 Dear Ms. Davis, The American Supply Association (ASA) is submitting its support for rejecting the automatic appeal the IAPMO Standards Council is considering related to an association amendment reviewed and rejected at the IAPMO Annual Membership meeting held in Anchorage, AK from September 25 – 28, 2017. The proposed association amendment was to remove the exception currently provided in item 603.4.1 of the UMC even though the proposal to delete the exception was previously rejected by the UMC Technical Committee. ASA is in full support of the UMC Technical Committee (TC) decision to reject the proposal submitted as Item #072 (see below) and keep the exception for residential occupancies in the UMC:

603.4 Factory-Made Air Ducts and Connectors. (remaining text unchanged) 603.4.1 Length Limitation. Factory-made flexible air ducts and connectors shall be not more than 5 feet (1524 mm) in length and shall not be used in lieu of rigid elbows or fittings. Exception: Residential occupancies.

As noted by the Air Conditioning Contractors of America (ACCA) and other commenters at the May 2017 meeting of the UMC TC meeting, the proposal to delete the exception was not accompanied by field data in support of the proposal. Item 072 was fully discussed by both those in favor of the item and those opposed and after significant discussion and due process, the TC made the appropriate decision to reject the proposal.

In addition, the ACCA Manual D, which is referenced in the 2015 edition of the UMC and remains a mandatory part of the 2018 edition provides adequate guidance on the proper sizing and installation of flexible ducts. The removal of the exception statement under 603.4.1 would set a significantly poor precedent by not allowing for products that have been listed, designed and installed properly. The ASA requests that the IAPMO Standards Council reject the appeal and uphold the consensus decision made by the UMC TC to keep the exception for residential occupancies under item 603.4.1 of the UMC. Thank you for the opportunity to participate in the process and if you have any questions or need additional information please do not hesitate to contact me directly. Sincerely,

James G. Kendzel, MPH, CAE Director, Codes and Standards jkendzel@asa.net 630-467-0000 Ext. 217 Background on the ASA: The ASA represents wholesaler-distributors and their supply chain partners in the plumbing-heating-cooling-piping (PHCP) and industrial pipe-valve-fitting (PVF) industry, ASA membership is comprised of over 330 distributors, 120 manufactures, and 135 manufacturer representatives. ASA provides a forum for trading partners from around the country to discuss the critical issues facing them, and offers a menu of programs and services uniquely geared to their needs.

CORPORATE HEADQUARTERS 7101 ATCO DRIVE

FORT WORTH, TEXAS 76118-7098 PHONE: 800-877-3828

FAX: 800-366-3539 www.atcoflex.com

IAPMO Standards Council c/o Gabriella M. Davis, Secretary 4755 E. Philadelphia Street Ontario, CA 91761 Subject: 2018 UMC – Item #072 ATCO Rubber Products, Inc. respectfully requests that IAPMO retain the current exception for residential occupancies given in paragraph 603.4.1 (2015 UMC) for the 2018 UMC (Item #072), and not choose to restrict the use of flexible duct in residential construction. As a manufacturer of UL 181 listed and labeled flexible air ducts for over fifty years, and a responsible member company of the HVAC industry, ATCO has produced literally billions of feet of flexible duct, which have been installed in residential and commercial structures across the US and around the world. Much of that duct is currently in use in areas that adopt the UMC, and is performing as intended. Like all building products, flexible ducts should be installed properly, per the manufacturer’s recommendations. Our company and our industry organization (the Air Duct Council, or ADC) regularly publish and reinforce to the industry, these proper installation practices. The ADC Flexible Duct Performance & Installation Standard (Green Book), which is widely distributed to code bodies, contractors and other industry participants, outlines in detail the proper methods of installation, which if practiced, allow flexible duct to perform as a key component of a sound and efficient residential HVAC system. ATCO provides friction loss data to the industry, in graph form, electronic spreadsheet format, and on a slide rule calculator, to be used in designing flexible duct systems with ATCO products, per ACCA Manual D. The ADC provides an online training course on its website, at no charge, which also outlines proper installation. Of all the products that make up a well installed residential HVAC system, many of which are more technically complex than flexible duct, we believe it is inappropriate and unfounded to restrict the use of flexible ducts, or any product due to a “likelihood” of incorrect installation. ATCO urges the Council to reject Item #72 and retain the residential exception for the 2018 UMC. Thank you in advance for your consideration of our request. Sincerely, Chip Kirkland Vice-President Sales

California Building Industry Association

1215 K St ree t , Su i te 1200 • Sacramento , CA 95814 • (916) 443-7933 • fax (916) 443-1960

For facts and information on housing and homebuilding, visit "The Voice of Housing in California" at www.cbia.org California Homebuilders – Committed to Quality

October 27, 2017 IAPMO Standards Council c/o Gabriella M. Davis, Secretary 4755 E. Philadelphia Street Ontario, CA 91761 RE: Comment on the Appeal of UMC 2018 Item #72 Members of the IAPMO Standards Council: In accordance with the IAPMO Regulations Governing Committee Projects (RGCP), please accept this letter as a comment to the Standards Council regarding the appeal of UMC 2018 Item #72. Name, affiliation and address: Robert E. Raymer, PE Senior Engineer/Technical Director Representing: California Building Industry Association

1215 K Street, Suite 1200 Sacramento, California 95814

The California Building Industry Association (CBIA) is a statewide trade association representing over 3,000 member-companies involved in residential and light-commercial construction. CBIA member-companies are responsible for over 90% of the new homes built in California each year. Statement identifying the particular action to which the comment relates: CBIA is supporting the rejection of 2018 UMC Item #72 based on the failure of the code development process to achieve consensus. Argument setting forth the grounds for appeal: Please see the Attachment #1 to this letter. Statement of recommended council action: CBIA respectfully requests that the IAPMO Standards Council render a decision to reject Item #72. As indicated in an earlier communication, I respectfully request the opportunity to present testimony to the Standards Council at the November 15th meeting. Sincerely,

Robert E. Raymer, PE Senior Engineer/Technical Director

Attachment: Argument setting forth the grounds for appeal

Failure to reach Consensus: While state agencies such as the California Department of Housing and Community Development are certainly capable of addressing issues left unresolved by the national code-writing entities, it has been the longstanding desire by both industry and the local code enforcement community for the state to make as few amendments as possible to the national model codes. Unfortunately, it has become apparent that the IAPMO membership and Technical Committee have been unable to reach consensus on Item #72. As such, if this code change is included as part of the 2018 UMC, several California state agencies will be forced to resolve issues that were not addressed during the IAPMO code development process via state amendment(s) to the national model code. Performance and installation concerns raised by the proponent of Item #72: It would seem that duct performance issues raised by the proponent of Item #72 have been largely addressed by the passage of 2018 UMC Item #75. In addition, the California Energy Commission’s (CEC) Building Energy Code Standards require field testing and certification of all residential ducts anyway. Whether a duct system utilizes flex duct or metal/rigid duct to deliver the air, it needs to be designed and installed properly. Passage of Item #75 seeks to address basic design and installation issues associated with flex duct. And, the CEC’s requirements for duct design coupled with required duct testing (to insure leakage rates do not exceed a state-mandated maximum allowable level) provides the consumer with a quality installation and a cost-effective, energy-saving HVAC system. The success of such CA code provisions is evidenced by the fact that consumer “call-backs” regarding flex duct performance issues have virtually disappeared over the past 15 years.

More importantly, given the widespread effective use of flex duct across the nation, if specific problems with installation were identified, isn’t it be more appropriate to establish corrective installation practices (such as those adopted by the CEC and established by 2018 UMC Item #75) as opposed to effectively banning the product? Cost Impact Analysis: As regularly noted in national media, California is experiencing an affordable housing crisis and will be for some time. In our research of the cost impact associated with the potential implementation of Item #72, CBIA requested Rick Wylie to perform a cost impact analysis comparing the application of rigid duct versus flex duct in a typical production-style home. By way of background, Mr. Wylie is President of Villara Building Systems and has over 35 years of experience in residential HVAC installations. In addition, Rick has been a stakeholder in every update of the CEC’s Building Energy Efficiency Standards dating back to the early-1980s. For the basis of Mr. Wylie’s analysis, his team used a two-story home with 2,700 square feet of conditioned floor area. In addition, both installations assumed a minimum of R-6 insulation. After performing the initial analysis using flex duct, the flex duct was then replaced with spiral hard pipe and elbows. The increased costs were: Material: Duct system material increased by $2,578 (from $1,485 to $4,328). Labor: Duct system labor increased by $1,919 (from $871 to $2,924). Total: Total labor and material increased by $4,497 (from $2,356 to $7,252) almost 3 times the base cost.

Clearly, one of the biggest impacts was the increase in site labor: this proposed change would increase the HVAC labor by approximately 32 hours/home at a time when the labor market is already very tight. A cost not included in this analysis but raised in a recent meeting with CEC Staff relates to the need to use an air sealant on a rigid duct system, something not required for flex duct. This would result in an additional cost of $300 not included in the analysis above. Additional Design Considerations: In the simplest of terms, California single-family dwellings are going “vertical”. Over the past twenty years, new homes in California have moved away from the single-story, ranch-style design. Today, over 80% of the new homes built in California are two- and three-story dwellings. This presents a design challenge for architects as the attic spaces of these homes have become more crowded with structural framing members and HVAC equipment, an environment well suited for a product like flex duct. Other issues of concern raised in our initial challenge to this proposal: • In the early-1990’s, the California Energy Commission performed extensive field evaluation of

residential duct systems and discovered seriously high levels of duct leakage rates. At that time, metal duct systems were by far the most common duct system installed in California homes. As the CEC worked to reduce duct leakage rates and improve overall HVAC design, flex duct systems emerged as the predominate product in the California market. In addition to being significantly more cost-effective (approximately 1/3 the cost of a metal duct system), the CEC and industry were able to substantially reduce duct leakage rates through the effective installation of flex duct systems. This outstanding field installation experience has not only served to provide a higher level of customer comfort and satisfaction, it has also been accomplished at significantly less cost to the consumer than that associated with rigid metal duct systems.

• Having reviewed the supporting documentation associated with this proposal, there did not seem to be any field data supporting this limitation in residential applications. Friction loss/pressure loss and duct leakage can be common problems associated with any duct system which is why care should be taken in both system design and field installation in order to minimize such losses and maximize energy efficiency.

• Lastly, what about HVAC system retrofit jobs? The California Legislature recently passed SB

350 which, among other things, seeks to implement a significant increase in the energy efficiency levels of existing buildings. It is difficult to understand how to implement a cost-effective retrofit of a 20+ year old residential HVAC system, which initially used flex ducts, with a new system using only rigid metal ducts. Such a project presents serious design issues and would be prohibitively costly.

For the reasons cited above, we must respectfully request the rejection of Item #72.

Monday,October30,2017at2:22:48PMPacificDaylightTimeGabyDavis

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Subject: RE:FlexibleDuctMaximumLengthDate: Monday,October30,2017at12:49:42PMPacificDaylightTimeFrom: Wungluck,BradTo: GabyDavisAIachments: image001.png

GoodAOernoonGaby,Thankyouforthequickresponse.IaminstrongopposiSontoItem#072assubmiUedbyRandyYoung.ThecommiUeeshouldNOTpassthisitem.Brad Wungluck - CBO, CASpChief Building OfficialCity of Manteca, Building Safety Division1001 W Center Street, Manteca, CA 95337

209-456-8562(o)209-923-8955 (f)

www.surveymonkey.com/s/mantecabuilding CONFIDENTIALITY NOTICE: This communication with its contents may contain confidential and/or legally privileged information. It is solely forthe use of the intended recipient(s). Unauthorized interception, review, use or disclosure is prohibited and may violate applicable laws including theElectronic Communications Privacy Act. If you are not the intended recipient, please contact the sender and destroy all copies of thecommunication. From:GabyDavis[mailto:Gaby.Davis@iapmo.org]Sent:Monday,October30,201712:34PMTo:Wungluck,Brad<bwungluck@ci.manteca.ca.us>Subject:Re:FlexibleDuctMaximumLength

Mr.Wungluck,Thankyouforyourcommentsbelow.IpresumeyouarereferringtoanappealscheduledonNovember15,2017totheIAPMOStandardsCouncil,andIsuspecttheappealatissueis#02-18.CanyouclarifywhetheryouareinsupportoforopposiSontoItem#072asnotedinthefollowinglink

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youclarifywhetheryouareinsupportoforopposiSontoItem#072asnotedinthefollowinglinkunderappeal#02-18?hUp://www.iapmo.org/Pages/AppealsSchedule2017.aspxIwillthenshareyourposiSonwiththeStandardsCouncil.PleasealsoadvisewhetheryouintendonparScipaSngattheappealshearingorsimplyprovidingwriUencommenttosharewiththeCouncilmembers.Thankyou,--GabyGabriella Davis

Secretary, IAPMO Standards CouncilThe IAPMO Group – West Building4755 E. Philadelphia StreetOntario, CA 91761Direct Phone +1 909-472-4203Main Phone +1 909-472-4100Private Fax +1 909-472-4222www.iapmo.org

This transmission is intended only for use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential and exempt from disclosureunder applicable law. If the reader of this message is not the intended recipient, or the employee or agent responsible for delivering the message to the intended recipient, you arehereby notified that any dissemination, distribution or copying of this communication is strictly prohibited. If you have received this communication in error, please immediately notifythe sender and destroy this message. Thank you.

From:"Wungluck,Brad"<bwungluck@ci.manteca.ca.us>Date:Saturday,October28,2017at1:57AMTo:GabyDavis<Gaby.Davis@iapmo.org>Subject:FlexibleDuctMaximumLength Good Morning Gaby, Please use this as the official comment for the City of Manteca, California. The use of flexible ducts in residential construction has been in use fordecades. It’s has proven to be a useful and cost effective method ofconstruction for heating and cooling. After working in the sheetmetal field fornearly twenty years I have seen firsthand the benefits of its use. Allowing aspecial interest group to potentially control a code related topic such as thisis frightening for IAPMO. I can’t stress enough the negative ramifications thiswould have on housing affordability, construction jobs, as well as the hit thatIAPMO would take for limiting the use of flexible duct. Do not approve thislimitation. Regards, Brad Wungluck, CASpChief Building OfficialBuilding Safety DivisionCity of Manteca

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October 31, 2017 Gabriella Davis Secretary, IAPMO Standards Council The IAPMO Group – West Building4755 E. Philadelphia Street Ontario, CA 91761 Subject: Appeal of 2018 UMC Item #72 Submitted by David Dias Sheet Metal Worker’s Local 104 2610 Crow Canyon Rd Suite 300 San Ramon, Ca 94583 I support the appeal of 2018 UMC item #72 In May 2016, the UMC Technical Committee voted for item #72 which took away the residential exclusion of the limitation of flexible ducts to 5’-0”. In September 2016, it was passed at assembly by an overwhelming majority of the IAPMO membership. In May of 2017, after substantial lobbying by the flex duct manufactures, it was voted down by the TC. In September 2017, it was again passed at assembly by an overwhelming majority of the IAPMO membership. I would ask the Standards Council to support the decision made twice by an overwhelming majority of the IAPMO membership at the assembly meetings and once at the UMC TC.

Thank you for your consideration in this matter, David Dias

445 Hutchinson Ave, Ste. 550, Columbus, OH 43235 888-253-2128 / 614-345-4328 ph / 614-345-9161 fax

October 31, 2017

IAPMO Standards Council

c/o Gabriella M. Davis, Secretary

4755 E. Philadelphia St.

Ontario, CA 91761

Re: 2018 UMC – Item #72

Dear Ms. Davis,

On behalf of Heating, Air-conditioning & Refrigeration Distributors International (HARDI), I write to urge

the Standards Council to reject Item #72, which would amend section 603.4.1 of the IAPMO Uniform

Mechanical Code to restrict the use of "Factory-made flexible air ducts and connectors" to no more than

"5 feet (1524mm) in length and shall not be used in lieu of rigid elbows and fittings" for residential

occupancies.

By way of background, HARDI is a trade association of nearly 1,000 member companies, over 475 of

which are U.S.-based wholesale companies. More than 85 percent of HARDI's distributor members are

classified as small businesses that collectively employ over 35,000 U.S. workers, representing more than

$35 billion in annual sales and an estimated 80 percent of the U.S. wholesale distribution market of

HVACR equipment, supplies and controls.

In our original comments to this Council, HARDI cited several concerns with the proposal and urged its

rejection. Quite simply, our membership has discussed this proposal in multiple forums since its

introduction and we have yet to find a single HARDI Distributor who was supportive of this proposal. The

broad consensus was that the proposal would limit the ability of the professional contractor to diagnose

and provide the best option for a homeowner, is based upon a flawed study and conflicts with other

ANSI accredited standards.

It is our belief that the adoption of Item #72 would have serious negative consequences for the HVACR

Industry and most importantly the consumer. For these reasons, HARDI urges the Standards Council to

reject Item #72 and retain the residential exception for the 2018 UMC.

Sincerely,

Jon Melchi

Vice President, Government & External Affairs

Heating, Air-conditioning & Refrigeration Distributors International (HARDI)

614-345-4328

TAT flF (A( IFflPMA - R PlNPP fl(ThJ IMFP FR/tflF5 ANfl I-WM 1M( A(FNflV PflM Nfl fl RPflAThJ P

DEPARTMENT OF HOUSING AND COMMUNITY DEVELOPMENTDIVISION OF CODES AND STANDARDSSTATE HOUSING LAW PROGRAM2020 W. El Camino Avenue, Suite 200, Sacramento, CA 95833P.O. Box 1407. Sacramento. CA 95812-1407(916) 445-9471 / FAX (916) 263-4713From TDD Phones 1-800-735-2929ov

October31, 2017

Gabriella DavisSecretary, IAPMO Standards CouncilThe IAPMO Group — West Building4755 E. Philadelphia StreetOntario, CA 91761

Dear Ms. Davis:

Subject: Appeal to Standards Council

Reference: Item #072 2018 Uniform Mechanical CodeSection 604.4.1 Length Limitation, Exception

Thank you for the opportunity to submit comments and attend the InternationalAssociation of Plumbers and Mechanical Officials’ (IAPMO) Standards Council meetingon November 15, 2017.

The Department of Housing and Community Development (HCD) is responsible forreviewing model codes, such as the 2018 Uniform Mechanical Code, for application toresidential structures. In addition, HCD’s State Housing Law (SHL) Program’s missionis safeguarding affordable housing through the adoption of uniform statewide minimumbuilding standards that protect the health, safety, and general welfare of the public andoccupants of housing and accessory buildings on a statewide basis.

HOD has concerns with approval of Item #072, which would prohibit the use of factory..made flexible ducts in residential occupancies to 5 feet or less.

Conflicts between technical experts. HOD has followed this proposal through IAPMO’scode development process, testified and observed considerable differences in opinionregarding the merits of this proposal. This is evidenced by a cycle of denials andapprovals for this proposal during the current !APMO code development process. Asimilar proposal was also rejected in the prior cycle.

Gabriella DavisSecretary, IAPMO Standards CouncilPage 2

Reduction in energy efficiency. This was the basis for the proposal; however, it is unknownwhether the energy loss resulted from improper sizing and installation of the flexibleducts. Further, the Uniform Mechanical Code is not an energy efficiency code nor is itsconstituency comprised of energy efficiency experts. The California Energy Commission (CEC),tasked with reducing energy costs, also has concerns with the proposed 5-foot length limitationfor flexible ducts. Some of the CEC’s concerns with limiting use of flexible ducts includedifficulty in field fabricating and extending ducts through trusses, the thermal integrity of fieldinstalled duct insulation meeting the California Energy Code’s R-6 duct insulation requirements,and difficulties with sealing seams along the length of duct and retaining permanent sealing ofthe duct system. The California Energy Code also requires all new duct systems to conform toa minimum installed performance for airflow of 350 cfm/ton of cooling while consuming a nomore than a maximum of 0.58 watts/cfm from the air handler fan. Duct systems comprised offlex duct are subject to this duct efficiency requirement and mitigates improper or poorinstallation of flex duct, thus eliminating a need to restrict their installation to only 5 feet lengths.

Firefighter safety issues. Some of the discussion surrounding Item #072 focused onfirefighter safety and dangers associated entanglement in wiring leftover from burnedflexible duct. Firefighters vertically ventilate roofs and attic space at ceilings. However,they are not walking in rafter spaces to be entangled. Flex duct is generally run acrossthe bottom chords of rafters or in between the webs of trusses, If there were significantburn damage firefighter would need to be concerned with more than just flex duct coils.In addition, it is not clear whether limitations to 5 feet would address this safety issue orif there is a more appropriate length that would allow the material to be used for itsmanufactured purposes.

Product performance. The draft 2018 UMC, Section 309.3 Installation Practices,requires that mechanical systems be installed in a manner that is in accordance with thecode, applicable standards, and the manufacturer’s installation instructions. There hasbeen significant disagreement among experts related to performance of flexible ducts.In most cases, it appears that poor performance is related to improper design, sizing,use or installation - issues that would not occur if the material had been installed incompliance with Section 3093. Wouldn’t the same or similar problems occur ifimproper design, sizing. use or installation methods were applied to other types of ductmaterial? We believe so, therefore it is not a code enforcement issue as much as atraining and education issue.

Use of alternate materials and methods of construction. The 2018 Uniform MechanicalCode, Section 302.2, provides for the use of systems, methods, or devices of equivalentor superior quality, strength, fire resistance, effectiveness, durabiNty, and safety overthose prescribed by the code. If the use of flexible ducts is common practice and a safeand economical alternative to use of other duct materials, Item #072 may result in caseby-case requests for app••• royal of flexible d cts especially in building areas, throughtrusses and tight spaces, where other materials are more labor intensive. costly anddifficult to instafl,

Gabriella DavisSecretary, IAPMO Standards CouncilPage 3

Fiscal lmøacts. The proposal should have provided an idea of the cost of restricting theuse of flexible duct material in residential applications. Although the lower cost offlexible duct may need to be weighed against its perceived lesser durability, it still needsto be compared with the alternate available materials.

HCD strongly recommends that Item #072 not be published in the 2018 UMC, This isbased on the disagreements among technical experts; lack of scientific data to supportthe length limitation for purposes of decreased energy efficiency; and lack of data on thecosts vs. benefits of the proposal to residential structures.

Please contact Stoyan Bumbalov at (916> 2634715 or by email atStoyanBumbalovhcd.ca.qov if you have any questions or need further information.Stoyan will be addressing the Council on November 15.

Sincerely,

/ /

Emily WithersCodes and Standards Administrator IIState Housing Law Program

JULIUS A. BALLANCO, P.E. President

JB ENGINEERING AND CODE CONSULTING, P.C.1661 Cardinal Drive • Munster, IN 46321

Phone: 219-922-6171 Fax: 219-922-6172

E-Mail: JBEngineer@aol.com

October 27, 2017

IAPMO Standards Councilc/o Gabriella DavisSecretary, IAPMO Standards CouncilThe IAPMO Group – West Building4755 E. Philadelphia StreetOntario, CA 91761

Dear Standard Council Members:

UMC Item Number: #072Proponent of Item: Randy YoungAction Being Sought: Rejection of Item

I am writing this letter of support for the rejection of Item #072 of the Uniform Mechanical Code,which has been appealed. The Mechanical Technical Committee has voted to reject this Item. Isupport that rejection.

In accordance with the engineering code of ethics, I must inform you that one of my clients is DaikinU.S. Goodman Manufacturing is a Daikin Company. Goodman also owns QuietFlex, a manufacturerof flexible duct. While there is a connection between my client and a manufacturer of flexible duct,I am not writing on their behalf. They have other consultants that are providing engineeringconsulting regarding this matter. I am writing as a very concerned member of IAPMO.

I, like many of my fellow members of IAPMO, have worked diligently to make the UniformMechanical Code the finest code for regulating mechanical systems. There have been many advancesmade in that regard. However, I consider this code change to be so detrimental that it will cancel outall of the good that has been accomplished in this code. It will make the Uniform Mechanical Codelook that bad. As the old saying goes, “One Ah shucks, will wipe out 10,000 Ata Boys.”

I was so distraught with the thought of this Item gaining approval that I testified at the AnaheimTechnical Committee meeting. During my testimony, I mentioned my connection to QuietFlexthrough Daikin U.S. At that meeting, the Mechanical Technical Committee voted to reject Item#072. This rejection was confirmed through letter ballot.

I liken the testimony on flexible duct to the arguments we sustained more than 25 years agoregarding the use of plastic pipe in plumbing. Those arguments were basically, “I don’t like the pipe,so don’t allow it in the code or place a ridiculous restriction on its use.” That is what this argumenthas resulted in for flexible duct, “I just don’t like it.”

October 27, 2017IAPMO Standards CouncilPage 2 of 3

I state this because there is no technical justification for limiting the amount of flexible duct in asingle family dwelling to 5 feet. One can easily ask, “Why 5 feet? Why not 4 feet? How about 6 feet?Why not 20 feet?” The argument over an arbitrary number can go on and on.

Of course, that is why the consensus process relies so heavily on the technical merits of any proposedchange. For Item #072, there are no technical merits regarding this proposed modification. Theproponent lists, as a part of his technical justification, “Flexible ducts create energy loss throughfriction.” This is one of those “duh” statements. In Fluid Mechanics 101, you learn that any fluidmoving through a conduit has friction loss on the surface of the conduit. In this case, the fluid is airand the conduit is flexible duct. Hence, the same statement can be made about any duct material. Itcan also be made about any piping material.

The proponent continues by stating, “HVAC and its components are the largest energy drain in anybuilding.” This statement, unfortunately, is completely false. Whether it is ignorance or lack ofknowledge, this statement shows the imprudence of this code change proposal. When the term isapplied to buildings (it normally applies to the human body), it is referring to waste or loss of energy.

A building’s HVAC system is a very energy efficient system. The drain on energy would be poorquality of windows or doors, or lack of insulation when associated with human comfort. The HVACsystems of today have improved by more than 60 percent over the systems of 40 years ago. Hence,there is no energy drain as the proponent states.

The further lack of knowledge becomes evident in the last statement, that reads, “Reducing energycost by installing efficient duct systems limiting the friction loss is essential to building comfort,longevity and cost savings through energy consumption.” The proponent is attempting to identifythe energy use for an HVAC system with duct friction loss. That makes absolutely no sense. Basedon this statement, we should simply install ductless systems in all buildings.

What the proponent fails to understand, regarding energy and the design of HVAC systems, is thatfriction loss and energy demand to provide heating and cooling are independent of one another.Heating and cooling is accomplished within the unit. That is the high energy use. From the unit, afan moves the heated or cooled air to the remainder of the building. The energy to operate the fanis minimal by comparison to the energy required to heat or cool the air. Furthermore, the energy fora fan in a residential unit is clearly established by the manufacturer. Unlike commercial installations,you cannot simply order a fan with higher pressure loss characteristics.

Having designed a number of residential systems, I can state that the value used by designers forresidential units is 0.5 inches of a water column in pressure loss for the fan. There are somemanufacturers that go up to 0.8 inches of a water column, but the standard for residential air handlingunits is 0.5 inches of a water column. As such, we size the duct system using this value.

October 27, 2017IAPMO Standards CouncilPage 3 of 3

It doesn’t matter whether the duct is sheet metal, plastic, or flexible, the pressure loss remains thesame. When sizing, you use the values for the material (roughness or smoothness), the velocity offlow through the duct, the number of fittings, and the length of the duct. All of these factors are takeninto consideration. Notice that duct material is only one part of the sizing equation.

It is a known fact with designers that flexible duct has a higher friction loss than sheet metal duct.Furthermore, there is a difference in sheet metal duct between round duct and rectangular duct.Round duct will always flow better. Hence, these are factors that are considered when designing asystem.

The proponent would tend to imply that, because there is a higher friction loss in flexible duct than sheet metal duct, it should be limited to 5 feet. Using this same analogy, there is a higher friction lossin rectangular sheet metal duct compared to round sheet metal duct or plastic duct, therefore,rectangular sheet metal duct should be limited to 5 feet. That last statement makes absolutely nosense. Similarly, the 5 foot limitation on flexible duct also makes no sense.

We don’t base the code on our likes or dislikes; we base it on the technical merits. There is notechnical reason for NOT allowing the unrestricted use of flexible duct in a residential HVACsystem. There is no technical justification for limiting the use of flexible duct to 5 feet in a residentialinstallation.

Following the consensus process, I believe it is imperative that the Standards Council reject UniformMechanical Code, Item #072.

Respectfully submitted,

Julius Ballanco, P.E.President

October 31, 2017 Transmitted via email IAPMO Standards Council Attn: Gabriella M. Davis, Secretary 4755 E. Philadelphia Street Ontario, CA 91761 Subject: Comment on Appeal of Uniform Mechanical Code - 2018 Item #072 IAPMO Standards Council: These comments are submitted by Eric Adamczyk, a Senior Research Associate, on behalf of Johns Manville regarding proposal #072 to the 2018 Uniform Mechanical Code (UMC). Johns Manville is a leading manufacturer and supplier of fiber glass insulation that used to insulate HVAC metal ducts as well as insulation used in flexible ducts. Johns Manville urges that the IAPMO Standards Council reject item #072 which proposed to limit the length of flexible duct in residential occupancies and urges that the current exception for residential occupancies given in paragraph 603.4.1 (2015 UMC) be retained. No technical justification has been provided to support limiting the use of flexible air duct in residential occupancies to a five foot maximum length. Different duct materials exhibit different friction characteristics. Thus, it is important that air ducts be properly sized to account for pressure drop in a duct system. Data on pressure drop and duct sizing is provided by duct manufactures, industry groups, and trade associations to permit proper duct sizing and design. If a particular duct system has a higher pressure drop for a given duct size than an alternative duct system, then duct size will typically be increased to meet duct system requirements and to provide comparable pressure drop performance. This is common engineering and duct design practice.

An arbitrary length limitation on the length of one duct type based on the fact that the pressure loss at a specific duct size is higher than for another duct type is neither warranted nor substantiated. Designers and installers should take into account the pressure loss characteristic of the particular duct system and material that is being selected, and contractors should install the product per manufacturer’s requirements, regardless of the duct type used.

Part 6 (California Energy Code) of California Title 24 requires that HVAC duct systems be tested to demonstrate compliance with stringent leakage, airflow, and fan efficacy requirements. Flexible duct systems are the most common HVAC duct system utilized in

California residential occupancy buildings, and the effectiveness of flexible duct systems in meeting California Title 24 requirements has been demonstrated on numerous installations.

Flexible Air Ducts listed and labeled to ANSI / UL181 Standard have been installed throughout the country for more than 40 years without an arbitrary limitation on installed length. Flexible Air Ducts are not limited in length in this standard nor are they limited in any other referenced standard. This code should be consistent with, and not more restrictive than the referenced consensus standards.

Johns Manville requests the Standards Council REJECT Item #72, thereby retaining the exception for residential occupancies.

Sincerely,

Eric Adamczyk Senior Research Associate Johns Manville

Date: 10/30/17 IAPMO Standards Council Ms. Gaby Davis 4755 East Philadelphia St. Ontario, CA 91761

Subject: Proposed Amendment to 2018 UMC 603.4.1, Item #072

Greetings,

Johnson Controls strongly urges the IAMPO Standards Council to retain the current exception for residential occupancies found under paragraph 603.4.1 in the 2015 UMC for the pending 2018 edition. Johnson Controls manufacturers Flexible Air Duct and HVAC equipment for both commercial and residential applications. We produce tens of millions of feet of Flexible Duct and hundreds of thousands of commercial and industrial HVAC units annually without issue. Johnson Controls finds that item #072, which proposes to amend 603.4.1 by deleting the current exception for residential occupancies, to be void of reasonable technical justification. Friction loss or pressure loss can occur with any duct system, regardless of the physical make. Properly sized and installed duct systems provide the consumer with excellent overall system performance and affordability.

The Air Conditioning, Heating, and Refrigeration Institute’s Project Number 8002 published in April 2014, “The Impact of Duct Design on Life Cycle Cost of Central Residential Heating and Air-Conditioning Systems,” fully examines the cost and performance impact of both Flex and Rigid Duct systems in the same single family homes in Chicago, Illinois and Austin, Texas. The study concludes Rigid Duct systems are two times the cost of Flexible Duct including material and installation, while achieving the same performance levels.

Based on the AHRI report a five (5) foot limitation of Flex Duct in residential occupancies would unjustly burden consumers without any tangible benefit or justification. The technical documentation provided for this proposal references poorly installed Flex Duct. Because of this issue, item #75 was written and adopted by both the Technical Committee and the General Assembly. Item #75 addresses basic design and installation issues with Flex Duct. For reasons cited above, Johnson Controls strongly recommends the IAMPO Standard Council reject item #072.

http://built-envi.com/wp-content/uploads/2012/11/stephens_iit_ahri_final_report1.pdf

Sincerely,

Matthew Meyer, Product Manager Flexible Air Ducts

5030 Corporate Exch. Blvd. SE, Grand Rapids, MI 49512 P 616 656 8200 F 616 656 6399 hartandcooleyinc.com

October 27, 2017

IAPMO Standards Council c/o Gabriella M. Davis, Secretary 4755 E. Philadelphia Street Ontario, CA 91761 VIA EMAIL

Subject: Comments on 02-18B JShapiro Appeal UMC Item #072

Members of the Standards Council:

In accordance with Section 1-6.4 Other Submissions Relating to an Appeal, please accept this letter as a formal comments to the Standards Council regarding the final disposition of UMC 2018 Item #072. The following information is provided as prescribed in Section 1-6.4:

(a). Name, affiliation and address of the appellant:

Donald M. Surrena, CBO National Association of Home Builders 1201 15th Street, NW Washington, DC 20005

Representing: National Association of Home Builders (hereafter “NAHB”)

NAHB is a federation of more than 700 state and local associations representing more than 140,000, member firms nationwide. NAHB’s members are involved in home building, remodeling, multifamily construction, land development, property management, and light commercial construction. Collectively, NAHB’s members employ more than 1.26 million people and construct about 80 percent of all new housing units constructed within the U.S. each year.

(b). Statement identifying the particular action to which the appeal relates:

NAHB is hereby commenting on the Appeal to the 2018 code development process outcome on 2018 UMC Item #072, which has been referred to the Standards Council as required by RGCP Section 4.6.1(c) based on failure of the Code Development Committee to achieve consensus.

(c). Argument setting forth the grounds for appeal:

Please see Attachment 1 to this letter.

(d). Statement of the precise relief requested:

In accordance with 1-6.4, NAHB requests that the Standards Council render a decision to REJECT Item #072, which upholds the consensus position of the Code Development Committee on Public Comment 2.

Thank you for considering this request, and I hereby request an opportunity to present our case in person at the upcoming Standards Council hearing in November.

Sincerely,

Donald M. Surrena, CBO

Attachment 1

Grounds for NAHB supporting 02-18B Appeal of UMC Item #072 Executive Summary

There are both technical and procedural problems with item #072. With respect to technical content, Item #072 should be rejected based on a lack of technically substantiation. From a procedural perspective, NAHB as an ANSI developer is concerned about the failure to follow ANSI procedures. IAPMO has not achieved consensus with respect to supporting adoption of the amendment recommended by Item #072. In addition, the appeal presents evidence demonstrating that some Technical Committee members failed to comply with the IAPMO Regulations Governing Committee Projects (RGCP) and the Guide for the Conduct of Participants in the IAPMO Codes and Standards Development Process (Guide). With regard to the information above, we respectfully request that the Standards Council approve appeal 02-18B JShapiro by assigning a final action on Item #072 of REJECT. The following is provided as a summary of the primary issues supporting the appeal. NAHB may bring forth additional supporting evidence in our oral presentation to the Standards Council at the appeal hearing. Failure to achieve consensus.

In considering this issue, it is important for the IAPMO Standards Council to protect the integrity of IAPMO’s consensus code development process: As an ANSI accredited standards developer NAHB understands the importance for IAPMO to defend the credibility of their consensus process to assure changes to the UMC are substantiated by a consensus decision. Clearly, in the case of UMC Item #072, there is a lack of consensus to justify making the requested change. I am a member of the UMC Technical Committee (TC) and the TC is the body charged with overseeing the UMC code development activity on behalf of IAPMO. It is the TC that is a consensus body that has balanced representation among many varied stakeholder interest groups. The TC has repeatedly rejected Item #072 by a substantial majority in the public comment and assembly action portions of IAPMO’s code development process. Looking at the history of the current section “603.4.1 Length Limitation” came in the 2015 edition, the section length limitation was rejected until the residential exception was added. As part of the IAPMO process, members who are in attendance at their membership meetings are given an opportunity to weigh in on TC recommendations, and in the case of Item #072, the members who attended IAPMO’s conferences have supported banning any use of flexibly duct in excess of five foot lengths. However, these “assembly action” votes are NOT consensus actions because there is no effort to balance the stakeholders who are at the membership meeting. Likewise, the votes are not representative of the IAPMO membership as a whole because only those members who are motivated and able to attend the meeting are able to vote. The entire IAPMO membership perspective is unknown, and irrespective of that, even the entire IAPMO membership is NOT a consensus body. Clearly, with only 37.5% of the TC supporting the IAPMO membership Assembly Action, IAPMO is nowhere near the point of reaching a consensus on this issue, and lacking consensus, the Standards Council needs to reject the flexible duct restriction and leave the section as it currently reads with the Exception: Residential occupancies.

Lack of technical merit

No data was provided to prove deficiencies of flex duct. Data was provided to the committee showing flex duct performed as well as any other duct product. Creditable data was provided showing the extreme increase in construction cost (in excess of $5,000 for each average sized single family dwelling) if the exception for residential construction was removed. NAHB studies have found nationally, for every $1,000 increase in the price of a home, about 152,903 households are priced out of the market for a median-priced new home. These are the households that can qualify for a mortgage before a $1,000 increase but not afterwards. The degree of impact varies between regions and depends largely on population and income distribution of each metro area. Using California as an example, for every $1,000 increase to the cost of a new home roughly 15,328 perspective buyers will not qualify for a mortgage. So a $5,000 increase would disqualify over 76,640 future home buyers from qualifying for their mortgage. All objections were heard and sufficient data was produced to rebut the assertions of poor performance of flex duct. The technical committee has twice returned the same decision that the residential exception should remain. This is the same language which is in the 2015 UMC. Item #75 was passed and will be a part of the 2018 code, which set guidance for minimum installation criteria for flex duct, to augment the manufacturer’s installation instructions. This item was put into the UMC to work with flex duct in all applications without length limitations, including residential. This change was in response to the unsubstantiated claim that flex duct was not being installed properly.

11 Canal Center Plaza ▪ Suite 103 ▪ Alexandria, Virginia 22314 ▪ Tel: (703) 684-0084 ▪ Fax: (703) 684-0427

Transmitted VIA email October 30, 2017 IAPMO Standards Council attn: Gabriella M. Davis, Secretary 4755 E. Philadelphia Street Ontario, CA 91761 Subject: Comment on Appeal of Uniform Mechanical Code - 2018 Item #072 IAPMO Standards Council: These comments are submitted by Charles Cottrell on behalf of the North American Insulation Manufacturers Association (NAIMA) regarding proposal #072 to the 2018 Uniform Mechanical Code (UMC). NAIMA is the association for North American manufacturers of fiber glass, rock wool, and slag wool insulation products. NAIMA strongly urges the Standards Council to reject item #072 for the following reasons:

1. There is no technical justification provided for limiting the use of flexible air duct to 5 ft. All types of ducts, no matter what the shape or inner surface material, experience pressure losses which are taken into account when sizing the duct system.

2. If the use of flexible duct is limited to 5 ft. or less in residential construction this will essentially require all duct systems in residential construction to be made of sheet metal. Sheet metal duct systems typically have a greater number of joints that require sealing than a system made with flexible duct. These seams, if not properly sealed will likely result in a duct system that is leakier and less efficient than one made of flexible air duct.

3. Flexible air ducts are pre-insulated and therefore do not require added labor cost to insulate the exterior of the duct after the sheet metal system is installed.

4. There is no consensus between the IAPMO Technical Committee and the membership on this item.

Properly designed and installed flexible air duct systems provide excellent airflow characteristics and energy savings. Restricting the use of a particular material without technical justification reduces competition in the market place and therefore item #072 should not be approved. Thank you for your consideration of these comments and please contact me if you have any questions. Sincerely,

Charles C. Cottrell Vice President, Technical Services

OWENS CORNING WORLD HEADQUARTERS ONE OWENS CORNING PARKWAY TOLEDO, OHIO 43659 419.248.8000

IAPMO Standards Council c/o Gabriella M. Davis, Secretary 4755 E. Philadelphia St. Ontario, CA 91761 (sent via email) Subject: Support Letter Requesting Rejection of UMC Item 072 2018 UMC Item 072 in section 603.4.1 proposes to remove the residential occupancies exception to the flexible duct length limitation that was adopted during the 2015 code development process. Owens Corning supports the rejection of Item 072 thereby retaining the residential occupancies exception to the length limitation. Owens Corning provided written comments for item 072 as well as other items pertaining to flexible duct during the public comment period. These comments along with many others (Public Comment 2) were reviewed by the UMC Technical Committee during its May 2017 meeting after which the Technical Committee voted to accept Public Comment 2 thereby rejecting item 072 and thus retaining the residential occupancies exception. Owens Corning stands by its original comments rejecting any length limitations to flexible duct in the UMC. Studies indicate a potential cost increase of more than 2x on average (varies by region) when limiting the use of flexible duct in residential HVAC installations. Removal of the residential occupancies exception would result in considerable cost increase while potentially sacrificing energy efficiency and home comfort. Flexible ducts are inherently an energy efficient and low leakage duct material. They also provide good acoustic control, resulting in a quieter environment for homeowners. California homes today require duct systems to undergo testing and meet the necessary performance requirements as listed in the California Energy Commission Residential Compliance Manual Section 4 Building HVAC Requirements. Additionally, many states have adopted the recent editions of the International Energy Conservation Code (IECC), or recognize the RESNET standards, both of which call for proper duct design and leakage testing of all duct systems. While Owens Corning offers proven options for insulating all types of duct systems, our customers generally do not support artificially limiting the choice of their HVAC contactor, general contractor, home builder, remodeler, and homeowner customers, especially where no benefit is delivered in limiting choice and increasing costs. Owens Corning requests the IAPMO Standards Council sustain the May 2017 Technical Committee decision to maintain the residential occupancies exception, thus rejecting Item 072. Respectfully, Katrina Keeley Senior Engineer Owens Corning Science & Technology 2790 Columbus Rd. Granville, OH 43023

Katrina Keeley

October 30, 2017

Ms. Gaby Davis Executive Vice President of Global Operations IAPMO 4755 East Philadelphia St. Ontario, CA 91761 Subject: 2018 UMC – Rejection of Item #072 Quietflex, a division of Daikin Global, is a leading manufacturer of flexible air duct headquartered in Houston, TX. Quietflex strongly urges the Standards Council to retain the current exception for residential occupancies found under paragraph 603.4.1 in the 2015 UMC by rejecting Item #072 shown in the pending 2018 UMC edition. Quietflex has been supplying the HVAC industry with quality products since 1976 and today ships commercial and residential flexible air duct nationwide and to Canadian markets. Thousands of feet of our products are installed in residential applications each day without any performance issues or complaints. We internally track quality issues in the field and can honestly say that Quietflex experiences zero complaints for excessive friction loss, duct leakage or detrimental effects on HVAC equipment caused by our flexible air duct products. Quietflex air duct friction-loss testing is conducted by an accredited third-party laboratory in strict conformance to ANSI/ASHRAE Standard 120. Quietflex publishes slide rule type friction-loss ductulators based on this test data for the HVAC contractors. This provides them with the knowledge to properly size Quietflex air ducts that result in optimum high performance air systems using ACCA Manual D or other building air system design software. For convenience we also provide phone app and online ductulators as well. Proper installation of flexible duct is no more difficult than proper installation of any air duct product – it is a matter of the installer’s accountability through code enforcement. To single out flexible duct as a particular problem is unfounded. Please consider maintaining the residential occupancies exception for the 2018 UMC by rejection of Item #072. Sincerely,

Stan Rusek, PE Director of R&D Quietflex, division of Daikin Global 4518 Brittmoore Houston, TX, 77041

Ms. Gabrielle M Davis

Secretary, IAPMO Standards Council

Subject Appeal item 72

Thank you for allowing me few moments of your time to discuss the importance of restricting flexible duct in residential occupancies.

First off let me be very clear, Flex duct has a place in the construction industry, however it should not be, nor was it ever intended for complete HVAC system, as a matter of fact, I did locate the original patent for this product. In the patent, flexible ducts original intent was to make the final connections in a duct system( Run outs), typically in hard to reach areas, around tight corners, between tight spaces. Ironically the same configurations that generate the largest pressure drops in the HVAC systems, thus causing the units to work harder in order to get the air out.

One of the Flex duct manufacturers who sits on the UMC TC, likes to throw out the “arbitrary length limitations” these proposed lengths are not arbitrary, 5-6 feet of flex at the end of the duct runs will silence the air flow just enough to make the system quiet, without hampering the performance of the units capability to heat or cool a room or area. It is suggested in several research papers, flex duct should be as short as possible to achieve the final connection, 5-6 feet per run out. Flex duct manufacturers and home builders are up in arms, this will affect their profitability. For the flex manufacturers, it means less sales volume, for home builders, this mean care and consideration should go into, not only the design of the buildings, but also the way the building is constructed.

Friction loss, yes all ducts display some friction loss, however flex duct can exhibit friction loss as high at ten times that of Steel or rigid duct, is this acceptable? It should not be. The largest driver of friction loss is the helicular construction of this product, then add poor installation practices, tight bend, sags, and compression, which is present in EVERY, I mean every installation I have seen.

Randy YoungSacramento JATC

There are several different types of duct work used in HVAC systems, the “Highest Achievers” in the move to sustainable building are Metallic duct, because of its high recycle rates, cleanliness, sturdiness and smooth interior surface creating much less friction loss than any other material used in HVAC systems.

We also have heard the argument that the increased cost to install rigid duct far outweighs the advantage, many experts do not see it this way. Sure there may be a small upfront cost change to the homeowner, however, take into consideration, when the HVAC unit becomes old and needs replaced, you do not have to replace the rigid duct. Many HVAC contractors love the ability to upsell new duct work, hence again making profits for the contractors and flex manufacturers’, this is not what I understood the IAPMO UMC TC to stand for, we need to deliver the best possible product for longevity to the end user.

In closing, I urge the IAPMO Standards council to see through the rhetoric thrown out by flex manufacturers and put a product in the Uniform Mechanical Code that clearly protect the end users and is not so clearly motivated by commerce.

Randy YoungSacramento JATC

- INTERNAL -

October 26, 2017

Ms. Gaby Davis Executive Vice President of Global Operations IAPMO 4755 East Philadelphia St. Ontario, CA 91761 Subject: 2018 UMC – Item #072 Thermaflex, a division of Flexible Technologies, Inc., is a manufacturer of flexible air duct headquartered in Abbeville, SC. Thermaflex favors the retention of the current exception for residential occupancies given in paragraph 603.4.1 (2015 UMC) for the 2018 UMC. We have been supplying the HVAC industry with quality products since 1953 and today ship commercial and residential ducting worldwide. Thousands of feet of our products are installed in residential applications each day without any issues or complaints, and our external DPPM of less than 500 serves to substantiate the lack of quality issues in the field. Thermaflex experiences no complaints for excessive friction loss, duct leakage or detrimental effects on HVAC equipment caused by our duct products. Thermaflex duct friction-loss testing is conducted by accredited third-party laboratories in strict accordance with ANSI/ASHRAE Standard 120. Thermaflex publishes friction loss calculators to allow for easy and proper duct sizing and system design. This is analogous to other duct products and – for that matter – any engineered product requiring field installation. All such products require proper installation to perform at designed specifications. To single out flexible duct as a particular problem is unfounded. Simply because a given product is more or less “easy” to install or has less “likelihood” to be installed correctly does not justify restricting it within the code. Most components and systems governed by the code are substantially more complex and difficult to correctly install than is flexible duct. Proper installation of flexible duct is no more difficult than proper installation of these more complex products – it is a matter of the installer accountability through code enforcement. Please consider maintaining the residential occupancies exception for the 2018 UMC. Sincerely, Bo Carlay Director of Engineering Thermaflex 381 Carwellyn Road Abbeville, SC 29620