Answers and Analysis

This knowledge base, updated to include the analyses from the 2003 through the most recent editions of the Uniform Plumbing and Mechanical Codes, continues to be a premier source for engineers, inspectors, students, contractors and tradesmen. Questions come from a broad base of users, and answers are informal interpretations of the Codes provided by a committee of code officials and special experts - they are clearly stated and to the point. This updated site combines the most pertinent analyses from the previous manual and presents them together with those based on the most recent publications of the Uniform Codes. This makes the Answers and Analysis database one of the most valuable tools you as a member can access wherever you have an internet connection.

The Answers and Analysis tool makes it easy to search for relevant questions and answers, either based on keywords or specific sections/chapters of the code. To find questions related to specific topics, type in the keyword(s), select the code and the year and click "Search". To search for questions related to a specific section, type the section in the Section field and click "Search". To search a specific chapter or appendix, select either the UPC or UMC Table of Contents, and select the chapter/appendix from the list.

Click to search by UPC Table Of Contents Click to search by UMC Table Of Contents

UPC Table Of Contents

Chapter	Title
1	Administration
2	Definitions
3	General Regulations
4	Plumbing Fixtures and Fixture Fittings
5	Water Heaters
6	Water Supply and Distribution
7	Sanitary Drainage
8	Indirect Wastes
9	Vents
10	Traps and Interceptors
11	Storm Drainage
12	Fuel Gas Piping
13	Health Care Facilities and Medical Gas and Medical Vacuum Systems
14	Firestop Protection
15	Alternate Water Sources for Nonpotable Applications
16	Nonpotable Rainwater Catchment Systems
17	Referenced Standards
Appendix A	Recommended Rules for Sizing the Water Supply System
Appendix B	Explanatory Notes on Combination Waste and Vent Systems
Appendix C	Alternate Plumbing Systems
Appendix D	Sizing Storm Water Drainage Systems
Appendix E	Manufactured/Mobile Home Parks and Recreational Vehicle Parks
Appendix F	Firefighter Breathing air Replenishment Systems
Appendix G	Sizing of Venting Systems
Appendix H	Private Sewage Disposal Systems
Appendix I	Installation Standards
Appendix J	Combination of Indoor and Outdoor Combustion and Ventilation Opening Design
Appendix K	Potable Rainwater Catchment Systems
Appendix L	Sustainable Practices
Appendix M	Sustainable Practices
Appendix N	Impact of Water Temperature on The Potential for Scalding and Legionella Growth

UMC Table Of Contents

Chapter	Title
1	Administration
2	Definitions
3	General Requirements
4	Ventilation Air
5	Exhaust Systems
6	Duct Systems
7	Combustion Air
8	Chimneys and Vents
9	Installation of Specific Appliances
10	Boilers and Pressure Vessels
11	Refrigeration
12	Hydronics
13	Fuel Gas Piping
14	Process Piping
15	Solar Energy Systems
16	Stationary Power Plants
17	Referenced Standards
Appendix A	Residential Plans Examiner Review Form for HVAC System Design
Appendix B	Procedures to be Followed to Place Gas Equipment in Operation
Appendix C	Installation and Testing of Oil (Liquid) Fuel-Fired Equipment
Appendix D	Fuel Supply: Manufactured/Mobile Home Parks and Recreational Vehicle Parks
Appendix E	Sustainable Practices
Appendix F	Geothermal Energy Systems
Appendix G	Sizing of Venting Systems and Outdoor Combustion and Ventilation Opening Design
Appendix H	Example Calculation of Outdoor Air Rate

Keywords

Code

Code Year

Section

Match EXACT search terms

Match ALL search terms

Match ANY search terms

Questions matching UMC Chapter 1

4 results

UMC 2003 103 UMC 2006 103 UMC 2009 103 UMC 2012 103.0

Topic: Process Piping

1. Can you tell me whether or not process piping was intended to be part of the purpose (Section 102.0) and scope (Section 103.0)?

2. Can you tell me whether process piping was intended to be regulated by the code?

The intent of this code is to regulate the design and installation of systems and equipment which directly and indirectly have an effect on the building environment. This includes virtually all equipment or systems that use any form of energy, as evidenced by the wording in the first sentence of Section 103.0 of the UMC, which includes “miscellaneous heat-producing appliances.”

One area of enforcement which is often overlooked and neglected is industrial processing equipment. Even though the code does not directly address the many varieties of such equipment, it is the intent of the code and responsibility of the Authority Having Jurisdiction to regulate the installation and maintenance of this equipment.
The intent of the former Appendix B, and now Chapter 14 (2003/2006/2009), was to give the Authority Having Jurisdiction some ability to regulate this piping. Process piping is, as you pointed out, defined as being "outside" the scope of the plumbing and mechanical codes. It uses materials that are not recognized in the code, in systems that may not connect to any mechanical or plumbing system. Without this Appendix/Chapter, we would only have the fire code regulations concerning allowed amounts of these chemicals and no say as to where this piping could be located or what safety precautions should be taken. The design engineer is a critical part of the equation; he or she should provide information that includes installation methods and proper testing procedures.

UMC 2003 103 UMC 2006 103 UMC 2009 103 UMC 2012 101.3

Topic: Equipment Replacement

Is it mandatory to comply to the present code when chillers are replaced or do the old requirements from the original installation still apply?

Yes, as stated in Section 103.0 (101.3, 2012), "Additions, alterations, repairs and replacement of equipment or systems shall comply with the provisions for new equipment and systems..."

UMC 2006 104.2 402.2 UMC 2009 104.2 402.2 UMC 2012 102.2 402.2

Topic: Existing Installations

1. In existing buildings, if there is not outside air ventilated in the building and it was a requirement at the time the building was constructed, should there be a requirement to install fresh air if equipment is not being replaced and the only duct work being performed is a shifting and moving of grills?

2. If any work is being done in the building on the mechanical system/s should there be a requirement to install fresh air ventilation into the building if none is present?

3. If there is only one unit being replaced and or worked on, should the entire building be brought into compliance with fresh air requirements?

Comment
Issues with lack of ventilation (outside) air are an ongoing concern with existing structures.

1. Yes, hazardous conditions should be corrected immediately upon discovery. Section 102.2 (2012), 104.2 (2006/2009) stipulates that existing mechanical systems must not create a hazard to life, health or property. Check with the Authority Having Jurisdiction, if at the time of original construction the building design was approved and met the intent of the UMC, then the existing installation could remain.
2. New work would need to meet the requirements of the current UMC.
3. See previous answers.

UMC 2003 112.2 UMC 2006 112.2 UMC 2009 112.2 UMC 2012 111.2, 203.0 UMC 2015 104.2

Topic: Permit requirement

Should replacement of the condensing unit of a split system air-conditioner be exempt from requiring a permit as described in section 111.2 (3)?

No, replacement of the condensing unit would not be exempt from requiring a permit. The intent of Sections 102.1 and 111.2(3) of the 2012 Uniform Mechanical Code is for maintenance of and not alteration or installation of whole components. Section 102.1 states in part: “… the addition, alteration or, repair is in accordance with that required for a new mechanical system.” The condensing unit is no different from the furnace or evaporator coils which both require a permit. When replacing a condensing unit you are not replacing a like for like appliance. The installer may increase or decrease the tonnage of the appliance or the condensing unit may require a lower amperage load and requiring the installation of a fused disconnect.