Washington Administrative Code › Title 296 - Labor and Industries, Department of › Chapter 296-54 - Safety standards-Logging operations › Section 296-54-607 - Radio signal systems-Specifications and test procedures

Current through Register Vol. 24-14, July 15, 2024
All radio-signaling systems put into use must meet or exceed
				the requirements of this section. When systems are altered or repaired they
				must continue to meet these requirements.
(1) Radio equipment in use at cable logging
			 sites, which is primarily used for voice communication, must be on a separately
			 assigned frequency from radio equipment primarily used to initiate whistles or
			 other audible signaling devices or to control any machine, material handling
			 device or other equipment hazardous to employees.
(2) Radio-signaling systems used to transmit
			 whistle signals or control functions of equipment associated with skyline,
			 highlead, slackline, or cable skidder systems of logging must transmit and
			 decode only by the use of authorized multitone frequencies. Only sequential
			 tones may be used to transmit signals or control equipment when using carrier
			 frequencies of 154.57 or 154.60 MHz.
(3) All radio systems receiver sensitivity
			 must be able to attain 0.4 microvolt, or greater, for 12 dB SINAD ratio for VHF
			 frequencies and 0.5 microvolt, or greater, for UHF frequencies. When
			 interference is a factor, the receiver may be desensitized in the furtherance
			 of safety by a person qualified according to WAC
			 296-54-605(12).
(4) All radio signal systems must have
			 receiver spurious attenuation of at least 70 dB when measured by the 20 db
			 quieting method and image response attenuation of 60 db when measured by the 20
			 db quieting method.
(5) All radio
			 signal systems must have receiver selectivity of at least 80 db plus or minus
			 30 KHz, when measured by the E.*I.A. SINAD method.
(6) The receiver-decoder tone frequency
			 stability must not exceed 0.006 (0.6%) above or below the assigned tone
			 frequency.
(7) The drift of a
			 transmitter-encoder tone must not exceed 0.006 (0.6%) above or below the
			 assigned tone frequency.
(8) Parts
			 of the radio-signaling system affected by moisture, which may be subjected to
			 the entrance of moisture during use, must be weatherproofed. Transmitters must
			 be tested within fifteen minutes after being subjected to the following
			 conditions and must have the ability to continue functioning properly. The
			 transmitter and receiver must be placed in a humidity chamber for eight hours
			 where the humidity has been maintained at not less than ninety percent and
			 where a 40 degrees C. temperature has been maintained.
(9) Radio-signaling system units must operate
			 within tolerances specified at any temperature within the range of -30 degrees
			 C. to +60 degrees C.
(10) Switches
			 of transmitters used to send whistle signals or activate equipment associated
			 with high lead, slackline, or cable skidder systems of logging must be designed
			 so that two buttons, motions or a combination of these are required
			 simultaneously to cause activation of the system. Arrangement of the activating
			 switches must allow the operator to transmit signals easily but not easily
			 activate a control or command function accidentally.
(11) All receivers intended to be mounted on
			 or in the yarder or similar equipment, and all portable transmitters, must
			 continue to maintain specified mechanical and electrical performance during and
			 after being subjected to vibration of the magnitude and amplitude as follows:
(a) The equipment must be vibrated with
			 simple harmonic motion having an amplitude of 0.015" (total excursion 0.03")
			 with the frequency varied uniformly between 10 and 30 Hz and an amplitude of
			 0.0075" (total excursion 0.015") with the frequency varied uniformly between 30
			 and 60 Hz.
(b) The entire cycle of
			 frequencies for each group (i.e., 10 to 30 cycles and 30 to 60 cycles) must be
			 accomplished in five minutes and repeated three times.
(c) The above motion must be applied for a
			 total of thirty minutes in each direction, that is, the directions parallel to
			 both axes of the base and perpendicular to the plane of the base.