[Code of Federal Regulations]

[Title 30, Volume 1]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 30CFR27.38]



[Page 156]

 

                       TITLE 30--MINERAL RESOURCES

 

  CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR

 

PART 27_METHANE-MONITORING SYSTEMS--Table of Contents

 

                       Subpart C_Test Requirements

 

Sec.  27.38  Tests to determine adequacy of windows and lenses.



    Impact tests. A 4-pound cylindrical weight with a one-inch diameter 

hemispherical striking surface will be dropped (free fall) to strike the 

window or lens in its mounting or the equivalent thereof at or near the 

center. At least three out of four samples shall withstand the impact 

according to the following table:



------------------------------------------------------------------------

                                                                 Height

                Overall lens diameter (inches)                   of fall

                                                                (inches)

------------------------------------------------------------------------

Less than 4...................................................         6

4 to 5........................................................         9

5 to 6........................................................        15

Greater than 6................................................        24

------------------------------------------------------------------------





Lenses or windows of smaller diameter than 1 inch may be tested by 

alternate methods at the discretion of MSHA.