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
Title 11 - Federal Elections
Title 12 - Banks and Banking
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

18.66—Tests of windows and lenses.

(a) Impact tests. A 4-pound cylindrical weight with a 1-inch-diameter hemispherical striking surface shall be dropped (free fall) to strike the window or lens in its mounting, or the equivalent thereof, at or near the center. Three of four samples shall withstand without breakage the impact according to the following table:

Lens diameter, (D), inches	Height of fall, inches
D<4	6
4≤ D<5	9
5≤ D<6	15
6≤ D	24

Windows or lenses of smaller diameter than 1 inch may be tested by alternate methods at the discretion of MSHA.

(b) Thermal-shock tests. Four samples of the window or lens will be heated in an oven for 15 minutes to a temperature of 150 °C. (302 °F.) and immediately upon withdrawal of the samples from the oven they will be immersed in water having a temperature between 15 °C. (59 °F) and 20 °C. (68 °F.). Three of the four samples shall show no defect or breakage from this thermal-shock test.

Tips