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Minnesota Legislature

Office of the Revisor of Statutes


Subpart 1.

Required entrance controls.

An entrance that is used for personnel access to the high radiation area in a permanent radiographic installation must have:


an entrance control of the type described in part 4731.2220, subpart 1, item A, subitem (1), that reduces the radiation level upon entry into the area; or


conspicuous visible and audible warning signals to warn of the presence of radiation. The visible signal must be actuated by radiation whenever the source is exposed. The audible signal must be actuated when an attempt is made to enter the installation while the source is exposed.

Subp. 2.



The alarm system under subpart 1 must be tested for proper operation with a radiation source each day before the installation is used for radiographic operations. The test must include a check of both the visible and audible signals. Entrance control devices that reduce the radiation level upon entry as provided under subpart 1, item A, must be tested monthly.


If an entrance control device or an alarm is operating improperly, it must be immediately labeled as defective and repaired within seven calendar days. The facility may continue to be used during the seven-day period if the licensee implements the continuous surveillance requirements under part 4731.4190 and uses an alarming ratemeter.


A licensee must maintain records of alarm system and entrance control device tests required under this part and retain each record for three years after it is made.

Statutory Authority:

MS s 144.1202; 144.1203


29 SR 755

Published Electronically:

March 12, 2009