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City of Houston Codes and Amendments


City of Houston Newly Adopted Code Information

List of adopted codes

2006 International Residential Residential Code

(Chapters 12 - 24 are the Mechanical Code for Residential Structures)                                     

2009 International Energy Conservation Code                                            

For One and Two Family Dwellings and Multi-Family 3 stories or less - Effective January 6, 2012         

For Commercial Structures, including Residential Structures MORE than 3 stories - Effective September 2, 2011

2006 International Building Code with amendments

2006 Uniform Mechanical Code with amendments

2011 National Electrical Code - Effective 9/1/2011

Code amendments, and Code Words are available on City of Houston's website





ASHRAE 90.1 – 2007 Effective September 2, 2011

For Commercial Structures, including Residential structures more than 3 stories

Note: For Commercial it is necessary to use either the 2009 IECC in its entirety or ASHRAE 90.1 – 2007 in its entirety. Cherry picking will not be allowed.




New Fees – Effective January 1, 2012

Houston City Council approved Ordinance # 2011-1168 increasing several of the fees in the city Code, including the City of Houston Construction Code. For a list of fees and details visit the following website.





Houston Amendments to the 2006 Uniform Mechanical Code

Chapter 3 – General Requirements

§ 304.4 Anchorage of Appliances

Appliances designed to be fixed in position shall be securely fastened in place. Supports for appliances shall be designed and constructed to sustain vertical and horizontal loads within the stress limitations specified in the Building Code for the minimum basic wind speed.

Note: Houston wind speed is 125 mph 3 second burst

Exception: Replacement of appliances in kind need only match the fastening requirements of the equipment being replaced.

§ 305.2 Access to Appliances and Equipment on Roofs

305.2.1 - Appliances and equipment located on roofs or other elevated locations shall be accessible.

305.2.2 - In buildings where the point of access is more than fourteen (14) feet above grade, an inside means of access to the roof shall be provided.

§ 310.2 - Condensation Control

310.2.1 - Water-Level Sensing Devices - On units and other coils on a roof or above a ceiling that do not have a secondary drain or means to install a secondary drain pan, a water level sensing device shall be installed inside the primary drain pan. This device shall shut off the appliance in the event that the primary drain becomes restricted. Inline overflow devices installed in the primary drain line shall not be permitted.

Chapter 4 – Ventilation Air Supply

§ 408.3 Toilet rooms shall be provided with a fully operable exterior window at least 3 square feet in area: a vertical duct not less than 100 square inches in area for the first toilet facility, with 50 additional square inches for each additional facility; or a mechanically operated exhaust system capable of exhausting 50 cubic feet of air per minute for each w

ater closet or urinal installed in the toilet room. Such systems shall be connected directly to the outside. The point of discharge shall be a least 3 feet from any operable window.


Chapter 5 – Exhaust Systems

§ 503.1 General - Motors and Fans located on roofs shall be accessible as specified in § 904.10.3. A toilet exhaust fan shall automatically shut down when the associated air-handling units serving that space shuts down.

§ 504.7 – Nail Salon Exhaust – Nail Salons shall be exhausted to the exterior of the building at a rate of 200 cfm and provided with .22 cfm of outside makeup air per salon station. Each room provided with an exhaust system shall have air supplied to the room equal to 80% of the amount of air to be exhausted. When a stand-alone makeup air system is provided, it shall be interlocked to the exhaust fans.

§ 504.8 – Exhaust Termination – Exhaust ducts shall terminate outside the building unless otherwise approved by the authority having jurisdiction.

§ 507.2.3 – Field Applied and Factory Built Grease Duct Enclosures. Factory built grease duct enclosures shall be protected with a through-penetration fire-stop system classified in accordance with ASTM E814 having an “F” and “T” rating equal to the fire resistance rating of the assembly being penetrated from the point at which the duct penetrates a ceiling, wall, or floor to the outlet terminal. The factory-built grease duct protection system shall be listed in accordance with UL 2221, Standard for Tests of Fire Resistive Grease Duct Enclosure Assemblies and installed in accordance with the manufacturer’s instructions and the listing requirements.

Field-applied grease duct enclosures shall be protected with a through penetration fire stop system classified in accordance with ASTM E814 having an “F” and “T” rating equal to the fire resistance rating of the assembly being penetrated. The surface of the field fabricated grease duct shall be continuously covered on all sides from the point at which the duct enclosure penetrates a ceiling, wall, or floor to the outlet terminal, listed in accordance with ASTM E2336 Standard Test Methods for Fire Resistive Grease Duct Enclosure Systems, and installed in accordance with the manufacturer’s instructions and the listing requirements.

§ 510.1.8 – Ducts, Non-Grease

Ducts serving dishwasher exhaust shall be liquid tight and shall be constructed of aluminum or not less than 304 stainless steel.

§ 510.3.4.1 – Horizontal Ducts.

On horizontal grease ducts, at least one 20 inch by 20 inch opening shall be provided for personnel entry. If not possible, opening large enough for cleaning at twelve-foot intervals. Additionally, an access door shall be provided within two feet of any change in direction.

§ 510.3.4.3 – Vertical Ducts.

Where personnel entry is possible, access shall be provided at the top of the vertical riser to accommodate descent.

Adequate access for cleaning shall be provided on each floor at no more than 15 foot intervals

§ 510.8 – Termination of Exhaust Systems

  • A hinged up-blast fan supplied with flexible weatherproof electrical cable and service hold open retainer to permit proper inspection and cleaning
  • The ductwork shall extend a minimum of 18 inches above the roof surface and the fan discharge a minimum of 40 inches above the roof surface.
  • Safe Access

§ 511.2 Airflow

  • The air velocity through any duct shall not be more than 2500 feet per minute (FPM).

§ 508.1 Where Required

Type 1 hoods shall be installed at or above all commercial type deep fat fryers, broilers, fry grills, steam-jacketed kettles, hot-top ranges, ovens, barbecues, solid-fuel burning appliance, and similar equipment that produces comparable amounts of steam, smoke, grease, or heat in a food-processing establishment to collect and remove the grease and smoke. For the purpose of this section, a food processing establishment shall include any building or portion thereof used for the processing of food but shall not include a dwelling unit.

Type 2 hoods shall be installed at or above other commercial-type ovens, rotisseries, and dishwashing machines.


(1)   Direct vent dishwashers connected to an approved exhaust system.

(2)   Under counter, and enclosed single-batch low temperature chemical dishwashers (maximum 135 E F)

Exceptions for both type 1 and 2 hoods:

(3)   This requirement shall not apply to domestic type cooking equipment located in daycare facilities, churches, employee lunchrooms, or similar uses that are not more hazardous than kitchen facilities in an individual dwelling unit.

(4)   Cooking Equipment listed according to UL197

§ 514.0 – Use and Maintenance of Equipment.

The building owner is responsible for compliance with all operating and maintenance procedures specified in this code and by the manufacturer.

Chapter 6 Duct Systems

§ 602.2 – Combustibles within Ducts or Plenums.

Materials exposed within duct or plenums shall be noncombustible or shall have a flame spread index not greater than twenty-five (25) and a smoke developed index not greater than fifty (50), when tested as a composite product in general accordance with one of the following test methods: NFPA 255, Method of Test of Surface Burning Characteristics of Building Materials, or UL 723, Test for Surface Burning Characteristics of Building Materials, or CAN/ULC S102.2-M88, Standard Method of Test For Surface Burning Characteristics of Floor Coverings, and Miscellaneous Materials and Assemblies


Return-air and outside-air ducts, plenums, or concealed spaces that serve a dwelling unit shall be permitted to be of combustible construction. Floor joists or trusses shall not be located within a return air plenum.

This is particularly important for residential installations.

§ 602.4 – Joints and Seams of Ducts.

Joints of duct systems shall be made substantially airtight by means of tapes, mastics, gasketing, or other means. Sealant materials and methods of assemblage shall be in accordance with the manufacturer’s instructions and conform to SMACNA Method A.

§ 606.2 – Fire Dampers / Smoke dampers / CRD’s

§ 606.5 – Access and Identification.

Dampers shall be provided with an approved means of access large enough to permit inspection and maintenance of the damper and its operating parts. The access shall not impair fire-resistive construction. Access shall not require the use of tools, keys, or special knowledge. Access points shall be permanently identified visibly on the exterior of the duct and at the ceiling level by a label with letters not less than 1 ½ inch (25.4 12.7 mm) in height reading: SMOKE DAMPER or FIRE DAMPER. Access doors in ducts shall be tight fitting and suitable for the required duct construction, and access doors shall be not more than 2 inches less than the size of the duct up to 24 inches, and 24 inch by 24 inch in ducts of 28 inch dimensions or larger.

Chapter 9 Installation of Specific Equipment Appliances

  • Prohibited installation:
  1. oAir handling units shall not be located in the same room with gas utilization equipment.

Table Insulation of Ducts

Duct Location



Insulation Types

Mechanically Cooled

and Outside Air


Insulation Types

Heating Only



On roof or exterior of building

R-8, V, W

R-8, W

Located inside the building thermal envelope

R-5, V


Located outside the building thermal envelope

R-8, V

R-8, W

Note: Where ducts are used for both heating and cooling, the minimum insulation shall be as required for the most restrictive condition.

V – Vapor Retarders: Material with a perm rating not exceeding 0.5 perm (29 ng/Pa• s•m•2). All joints to be sealed

W – Approved weatherproof barrier

Houston Amendments to the 2009 International Energy Conservation Code

Significant Change to 2009 EICC

  • Texas A&M energy System Lab will not be issuing a duct trade off letter for the 2009 IECC. The substitution of SEER 14 rather than the SEER 13 system to allow R-6 insulation instead of R-8 duct insulation in the attic will no longer be provided as an option. However, you can still use R-6 if you do a performance method including use of the IC3, Rim-Rate software.

§ 403.1.1 Programmable thermostat

Where the primary heating system is a forced-air furnace, at least one thermostat per dwelling unit shall be capable of controlling the heating and cooling system on a daily schedule to maintain different temperature set points at different times of the day. This thermostat shall include the capability to set back or temporarily operate the system to maintain zone temperatures down to 55° F or up to 85° F. The thermostat shall be capable of being initially programed with a heating temperature set point no higher than 70° F and a cooling temperature set point no lower than 78°F.

§ 402.2.3 Access hatches and doors

Access doors from conditioned spaces to unconditioned spaces (e.g. attics and crawl spaces) shall be weather stripped and insulated to a level equivalent to the insulation on the surrounding surfaces…..


Pull down attic stair systems may be reduced to R-5 insulation at the stair access. The insulation shall not interfere with the proper operation of the stair. Non-rigid insulation materials are not allowed. Additional insulation systems that enclose the stair system from above are allowed. Exposed foam plastic must meet the provisions of the Houston Residential Code.