CFR

Title 1 - General Provisions
Title 2 - Grants and Agreements
Title 3 - The President
Title 4 - Accounts
Title 5 - Administrative Personnel
Title 6 - Domestic Security
Title 7 - Agriculture
Title 8 - Aliens and Nationality
Title 9 - Animals and Animal Products
Title 10 - Energy
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Title 13 - Business Credit and Assistance
Title 14 - Aeronautics and Space
Title 15 - Commerce and Foreign Trade
Title 16 - Commercial Practices
Title 17 - Commodity and Securities Exchanges
Title 18 - Conservation of Power and Water Resources
Title 19 - Customs Duties
Title 20 - Employees' Benefits
Title 21 - Food and Drugs
Title 22 - Foreign Relations
Title 23 - Highways
Title 24 - Housing and Urban Development
Title 25 - Indians
Title 26 - Internal Revenue
Title 27 - Alcohol, Tobacco Products and Firearms
Title 28 - Judicial Administration
Title 29 - Labor
Title 30 - Mineral Resources
Title 31 - Money and Finance: Treasury
Title 32 - National Defense
Title 33 - Navigation and Navigable Waters
Title 34 - Education
Title 35 - Panama Canal
Title 36 - Parks, Forests, and Public Property
Title 37 - Patents, Trademarks, and Copyrights
Title 38 - Pensions, Bonuses, and Veterans' Relief
Title 39 - Postal Service
Title 40 - Protection of Environment
Title 41 - Public Contracts and Property Management
Title 42 - Public Health
Title 43 - Public Lands: Interior
Title 44 - Emergency Management and Assistance
Title 45 - Public Welfare
Title 46 - Shipping
Title 47 - Telecommunication
Title 48 - Federal Acquisition Regulations System
Title 49 - Transportation
Title 50 - Wildlife and Fisheries

91.304—Test equipment overview.

(a) All engines subject to this subpart are tested for exhaust emissions. Engines are operated on dynamometers meeting the specification given in § 91.305.

(b) The exhaust is tested for gaseous emissions using either a constant volume sampling (CVS) system as described in § 91.414, or using the raw gas sampling system as described in § 91.421. Both systems require analyzers (see paragraph (c) of this section) specific to the pollutant being measured.

(c) Analyzers used are a non-dispersive infrared detector (NDIR) absorption type for carbon monoxide and carbon dioxide analysis; paramagnetic detector (PMD), zirconia (ZRDO), or electrochemical type (ECS) for oxygen analysis; a flame ionization detector (FID) or heated flame ionization detector (HFID) type for hydrocarbon analysis; and a chemiluminescent detector (CLD) or heated chemiluminescent detector (HCLD) for oxides of nitrogen analysis.

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