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The City of Portland, Oregon

Office of Management & Finance

Bureau of Revenue and Financial Services

Phone: 503-823-5288

Fax: 503-823-5384

1120 SW 5th Avenue, Rm 1040, Portland, OR 97204

Clean Air Construction Requirements

List of Public Agencies That Have Adopted the Following Clean Air Construction Requirements To Date

Agency Name Adoption Method Applicable Contract Value Dollar Threshold
City of Portland Sustainable Procurement Policy - Attachment 3 $1,000,000.00
Multnomah County Administrative Procedure PUR-10 $500,000.00
Washington County Procurement Rules $500,000.00


Idle Reduction Requirements

Beginning January 1, 2020 contractors working on City construction projects shall take the following steps to reduce unnecessary diesel equipment idling:

  • All nonroad diesel equipment must shut down after five (5) minutes of inactivity, and
  • All nonroad diesel equipment shall have decals/prompts visible to the operator to remind them to shut down the equipment after five (5) minutes of inactivity, and
  • Contractors will post “Five Minute Limit” signs in high foot traffic areas of the job site, visible to workers, and
  • Contractors will ensure all diesel equipment operators are aware of the policy.

Exemptions to the above idle reduction requirements are allowed in circumstances where:

  • the safety of contractors and their employees may be compromised if diesel equipment is turned off; for example, where employees are working in a trench; or
  • the equipment meets the most stringent EPA emissions standards or has been retrofit with a DPF; or
  • frequent shutdowns may be detrimental to the exhaust control system, reducing the effectiveness of that system by lowering the exhaust temperature; or
  • equipment requires testing, servicing, inspection, or repairs.

Diesel Engine Requirements and Phase-In Schedule

Effective January 1, 2021 and in accordance with the phase-in schedule outlined below all diesel-powered nonroad construction equipment greater than 25 horsepower and all on-road diesel dump trucks and cement mixers used on City construction projects must meet the following requirements:

Effective Date of Diesel Engine Requirement Nonroad Diesel (over 25 hp) On-Road Diesel (cement mixers and dump trucks)
January 1, 2020 Idle Reduction Requirements  
January 1, 2021 No tier 0 engines allowed1  
January 1, 2022 No tier 1 engines allowed1  
January 1, 2023 No tier 2 engines allowed1  
January 1, 2024 No tier 3 engines allowed1,2 No pre-2007 engines1,2
January 1, 2025 Tier 4 only1,2  
January 1, 2026 Tier 4 only3 No pre-2007 engines3
  • 1Diesel engine retrofits (emission control devices) allowed on older equipment/vehicles following the Compliance Options Protocol provided herein.
  • 2No new DOC emission control devices allowed. Equipment retrofitted with DOC emission control devices prior to 2024 are allowed.
  • 3No older equipment/vehicles allowed unless it was retrofitted with a DPF prior to 2026. Exemption: certified DMWESB or certified SDVB firms may use equipment/vehicles retrofitted with a DPF or DOC prior to 2024 (for DOCs) and 2026 (for DPFs).

Contractors may apply for exemptions to the above diesel engine requirements on a per project basis in circumstances where:

  • The equipment/vehicle is required for an emergency (including for underground equipment operators).
  • After following the Compliance Options Protocol, the required emission control device would obscure operator lines of sight or otherwise impact worker safety or the equipment is not able to be retrofit with a verified emission control device; and no compliant rental equipment is available within 100 miles of the job site.
  • After following the Compliance Options Protocol, the contractor can demonstrate that due to the uniqueness of the equipment/vehicle or similar special circumstances, it is not reasonable to comply with the diesel engine requirement for a specific piece of equipment/vehicle.

Compliance and Verification

Contractors (prime and sub-contractors, and applicable suppliers) will demonstrate compliance with the Clean Air Construction requirements on an annual basis by providing to the applicable contracting agency, or approved program operator, all requested diesel equipment/vehicle information needed to verify compliance, including confirmation that retrofit devices are maintained on the equipment in proper operating condition. Upon determining compliance with the requirements, the applicable contracting agency, or approved program operator, will issue an equipment/vehicle decal for each compliant piece of equipment/vehicle. This decal must be displayed on the compliant equipment/vehicle at all times in a location readily visible to agency staff. In addition, random on-site inspections by agency staff (or approved program operator) will be conducted on a project by project basis.  Additional details regarding consequences for noncompliance will be determined on an agency-by-agency basis.  Additional implementation/program elements are currently in development.

Compliance Options Protocol

Compliance with the Diesel Engine Requirements contained herein will be determined according to the following protocol:

Protocol Step Question(s) Answer  Action
  • Is the nonroad equipment over 25hp?
  • Is the on-road vehicle a cement mixer or dump truck?
 YES Go to Step 2
   NO Register equipment and obtain compliance verification. No further action required other
than anti-idling compliance on job-site.
 2 Is the equipment/vehicle required for an
emergency? (including for underground
equipment operators) 
 YES Request Exemption
   NO Go to Step 3
  • Is the equipment/vehicle powered by electricity or alternative (non-diesel) fuel?
  • Is the diesel cement mixer or dump truck 2007 or newer?
  • Does the diesel nonroad equipment utilize only a Tier 4 engine(s)?
 YES Register equipment and obtain compliance verification. No further action required other than anti-idling compliance on job-site.
     NO Go to Step 4
 4 Can the equipment/vehicle be repowered or retrofit
with a CARB or EPA verified DPF or equivalent?1  
 YES Repower or retrofit equipment and obtain compliance verification. 
  • If 2023 or earlier, go to Step 5.
  • If 2024 or later, go to Step 6.
 5 (pre-2024) Can the equipment/vehicle be retrofit with a CARB or EPA verified emissions control device other than DPF (or equivalent)?1    YES  Retrofit equipment with an emission control device that maximizes diesel particulate matter emission reduction. Obtain compliance verification. 
   NO Go to Step 6 
Is compliant rental equipment available within 100 miles of the job site?    YES Rent equipment and obtain compliance verification.
   NO Request Exemption.  
 1Equivalent is defined as achieving the same level (within 10%) of diesel particulate matter (PM) emissions reduction as a DPF.