Washington Administrative Code › Title 352 - Parks and Recreation Commission › Chapter 352-67 - Vessel sound level measurement procedures › Section 352-67-050 - Specific requirements

Current through Register Vol. 24-14, July 15, 2024
(1) A
		  person who is qualified to conduct sound level measurement procedures may use
		  either the shoreline sound level measurement procedure, or the stationary sound
		  level measurement procedure, or both.
(2) The shoreline sound level measurement
		  procedure shall be performed as follows:
(a) A
		  suitable measurement site is the shore of a body of water, or dock projecting
		  out from the shore into the body of water, or a raft, or a vessel moored to a
		  dock, or anchored so that the sound level meter or microphone is not more than
		  six meters (twenty feet) from shore. If the measurement is made from a dock,
		  the dock shall be of open construction so that it presents a minimum of
		  reflecting surfaces. The area around the microphone and vessel being measured
		  shall be free of large obstructions or reflective surfaces including but not
		  limited to buildings, high embankments, sea walls, hills, large piers, or
		  breakwaters, for a minimum distance of thirty meters (one hundred
		  feet).
(b) The applicable reading
		  does not require that the vessel subject to the procedure be at any specific
		  distance from the shoreline or microphone.
(c) This measurement procedure shall not be
		  used during the time period of thirty seconds following engine start up and/or
		  preceding engine shutdown.
(d) The
		  microphone shall be placed 1.2 meters to 1.5 meters (four feet to five feet)
		  above the water, and no less than 0.6 meter (two feet) above the curve of the
		  shore, dock, or platform. If on a dock or platform, the microphone shall be
		  placed near or beyond the end of the dock or platform. If the measurement is
		  made from a vessel, the microphone shall be held at a height of not less than
		  0.6 meter (two feet) above the surface of the water. A suitable vessel for this
		  purpose is of open hull construction.
(e) The meter shall be set for slow response
		  and the A-weighting network on the sound level meter.
(f) The observer reading the meter shall not
		  be closer than arm's length from the microphone. Only one other person may be
		  within fifteen meters (fifty feet) of the microphone when measuring from the
		  dock or shoreline, and that person shall be directly behind the observer
		  reading the sound level meter.
(g)
		  The applicable reading shall be the highest sound level measured during a
		  period when the background sound level is at least ten dB lower than the
		  maximum allowable sound level. Background sound level includes wind effects,
		  noise from boats other than the one being measured, wave action, boat wakes,
		  and other extraneous noises. Readings due to hull slaps which create
		  intermittent sound levels shall be disregarded.
(h) The observer shall record the applicable
		  reading and the background sound levels taken immediately before and
		  immediately after applicable reading.
(i) When sound level readings are taken from
		  inside a vessel, three dB shall be subtracted from the reading to better
		  correlate with shoreline readings.