Current through Register Vol. 47, No. 17, September 10, 2024
a. Operators will
submit a noise mitigation plan that demonstrates one or more proposed methods
of meeting the maximum permissible noise levels described by this Rule 423 as
an attachment to their Form 2As, as required by Rule 304.c.(2). An Operator may
submit substantially equivalent information or plans developed through a Local
Government land use process or federal process in lieu of the information
required by this Rule 423.a unless the Director or Commission determines that
the information or plan developed through the Local Government land use process
or federal process is not equivalent. The noise mitigation plan will include at
least the following information:
(1) An
explanation of how the Operator will comply with the maximum permissible noise
levels specified in Rule 423.b.(1). This is to include a description of methods
to design acoustical mitigation measures or choose/site equipment appropriately
such that the Operator has a reasonable expectation of compliance.
(2) Estimated duration of each stage of
operation, including drilling, completion, Flowback, production, and an
estimate of the noise levels of each stage of operation;
(3) Reference to topographical considerations
of noise and noise propagation at the proposed Oil and Gas Location;
(4) Description of Best Management Practices
and best engineering practices for measuring and mitigating noise levels and an
implementation schedule for such technology.
(5) For proposed Oil and Gas Locations with a
Working Pad Surface within 2,000 feet of one or more Residential Building
Units, at least one, and no more than six noise points of compliance where
monitors will be located. Operators will identify noise points of compliance
using the following criteria:
A. Provide one
noise point of compliance in each direction in which a Residential Building
Unit is located within 2,000 feet of the proposed Working Pad
Surface.
B. Noise points of
compliance will be located at least 350 feet from the Working Pad Surface, and
no less than 25 feet from the exterior wall of the Residential Building Unit
that is closest to the Working Pad Surface. If a Surface Owner or tenant
refuses to provide the Operator with access to install a noise monitor, then
the noise point of compliance will be located at either the next-closest
Residential Building Unit or an alternative location approximately the same
distance and direction from the Working Pad Surface.
b. A preliminary plan for how the
Operator will conduct background ambient noise surveys to establish baseline
conditions for noise levels on the site, for both A-scale and C-scale noise.
The Director may require as a condition of approval on the Form 2A that the
Operator conduct the background ambient noise survey between 30 and 90 days
prior to start of construction and update the plan accordingly based on the
results. Operators will conduct baseline noise surveys at the noise points of
compliance identified pursuant to Rule 423.a.(5). When an Operator conducts a
background ambient survey the Operator will follow the same approach as
outlined in Rule 423.c.(7) and over a 72-hour period, including at least 24
hours between 10:00 p.m. on a Friday and 4:00 a.m. on a Monday. Operators will
record any significant weather events and take those events into account when
establishing the baseline. A single cumulative daytime ambient noise level and
a single cumulative nighttime ambient noise level will be established by taking
the logarithmic average of all daytime or nighttime 1-hour Leq values measured
and in accordance with the sound level data collection requirements pursuant to
the maximum permissible noise levels.
(1) All
Oil and Gas Operations will comply with the following maximum permissible noise
levels in Table 423-1 unless otherwise required by Rule 423. The Director may
require Operators to comply with a lower maximum permissible noise level based
on the consultation process with Relevant and Proximate Local Governments,
CDPHE, or CPW pursuant to Rules 302.g, 309.e, & 309.f.
Table 423-1 - Maximum Permissible Noise
Levels
|
LAND USE DESIGNATION
|
7:00 am to next 7:00 pm
|
7:00 pm to next 7:00 am
|
|
Residential/ Rural/State Parks & State Wildlife
Areas
|
55 db(A)
|
50 db(A)
|
|
Commercial/Agricultural
|
60 db(A)
|
55 db(A)
|
|
Light Industrial
|
70 db(A)
|
65 db(A)
|
|
Industrial
|
80 db(A)
|
75 db(A)
|
|
All Zones
|
60 db(C)
|
60 db(C)
|
(2)
Unless otherwise required by Rule 423, drilling or completion operations,
including Flowback:
A. In Residential/Rural
or Commercial/Agricultural, maximum permissible noise levels will be 60 db(A)
in the hours between 7:00 p.m. to 7:00 a.m. and 65 db(A) in the hours between
7:00 a.m. to 7:00 p.m.; and
B. In
all zones maximum permissible noise levels will be 65 db(C) in the hours
between 7:00 p.m. to 7:00 a.m. and 65 db(C) in the hours between 7:00 a.m. to
7:00 p.m.
(3) The basis
for determining land use designation pursuant to Table 423-1 will be the
Relevant Local Government's land use or zoning designation. The Director may
consult with a Relevant or Proximate Local Government to identify the type of
land use of the Oil and Gas Location and its surrounding area, taking into
consideration any applicable zoning or other local land use designation.
A. To protect public health, safety, and
welfare, the Director may require Operators to comply with a lower maximum
permissible noise level in areas zoned industrial, light industrial, or
commercial, if the Oil and Gas Facility will be within 2,000 feet of a
Residential Building Unit or High Occupancy Building Unit.
B. In a noise mitigation plan submitted
pursuant to Rule 423.a, an Operator may request a higher maximum permissible
noise level than would otherwise be allowed by Table 423-1, if the Operator
demonstrates that both the Relevant and any Proximate Local Governments agree
to the higher maximum permissible noise level. The Director may apply that
higher maximum permissible noise level as long as the requested level is
protective of public health, safety, and welfare, and wildlife.
(4) When operating in High
Priority Habitat, Operators will consult CPW and, on federal lands, the Bureau
of Land Management, or United States Fish and Wildlife Service, to determine
the acceptable noise limits and monitoring protocols.
(5) Operators may exceed the noise levels in
Table 423-1 as measured at the nearest noise point of compliance if all
affected Surface Owners and tenants agree in writing to the higher noise limit
requested by the Operator.
(6)
Unless otherwise required by Rule 423.b.(7), during the hours between 7:00 a.m.
and the next 7:00 p.m. the maximum permissible noise levels listed in Table
423-1 may be increased 10 dB(A) for a period not to exceed 15 minutes in any
1-hour period. The increase is permissible only for a 1 hour period during any
12 hours.
(7) Operators will reduce
periodic, impulsive, or shrill noise by 5 dB(A) below the levels in Table
423-1. For periodic, shrill, and impulsive noise within 1000 feet of a
Residential Building Unit, Operators will minimize noise that can be readily
eliminated through maintenance, equipment modification, or other readily
available procedures.
(8) Pursuant
to Commission inspection or upon receiving a complaint from a Local Government,
or a Surface Owner or tenant of a property within 2,000 feet of an Oil and Gas
Facility regarding noise related to Oil and Gas Operations, the Commission will
conduct an onsite investigation and take sound measurements using the methods
prescribed for Operators in Rule 423.c.
c. To demonstrate compliance with Tables
423-1 and 423-2 Operators will measure sound levels according to the following
standards:
(1) During pre-production
activities and ongoing operations lasting longer than 24 consecutive hours such
as drilling, completion, recompletion, Stimulation, and Well maintenance, in
areas zoned residential or within 2,000 feet of a Building Unit, Operators will
take continuous sound measurements from each noise point of compliance
designated pursuant to Rule 423.a.(5).
(2)
Monitoring Procedures.
A. In response to a complaint or at the
Director's request, Operators will measure sound levels at 25 feet from the
complainant's occupied structure towards the noise source for low frequency
(dbC) indicated issues. For high frequency (dbA) measurement will be at the
nearest point of compliance. For equipment installed at Oil and Gas Locations
subject to a Form 2A approved prior to January 15, 2021, after the Commencement
of Production Operations, no single piece of equipment will exceed the maximum
permissible noise levels listed in Table 423-1 as measured at a point 350 feet
from the equipment generating the noise in the direction from which the
complaint was received.
B. In
situations where measurement of noise is unrepresentative due to topography or
any other issue, Operators or the Commission may take the measurement at the
nearest noise point of compliance, or at a different distance and extrapolate
it to 25 feet from the complainant's residence (dbC) or the complainant's
property line (dbA) using the following formula:
db(A) distance 2 = db(A) distance 1 - 20 x log 10 (distance
2/distance 1)
db(C) distance 2 = db(C) distance 1 - 20 x log 10 (distance
2/distance 1)
(3) Operators will equip sound level meters
with wind screens that are in good working order, and will take readings when
the wind velocity at the time and place of measurement is not more than 5 miles
per hour. In determining an Oil and Gas Operation's contribution to sound
levels, the Director will consider wind readings that exceed 5 mph.
(4) Operators will take sound level
measurements 5 feet above ground level.
(5) Operators will determine sound levels by
averaging logarithmic minute-by-minute measurements made over a minimum 1-hour
sample duration.
(6) All sound
meters will be type II meters at a minimum. All measurements will be reported
using LeqA (fast) and LeqC (slow). Meters will be field calibrated pre-survey
and post survey. Continuous surveys will be field calibrated pre-survey and
post survey and pursuant to the manufacturer's recommended interval. All survey
equipment will be inspected at time of calibration for compliance with the
Commission's Rules.
(7) Operators
will take samples under conditions that are representative of the noise
experienced by the complainant (e.g., at night, morning,
evening, or during special weather conditions).
(8) If a Building Unit, High Occupancy
Building Unit, High Priority Habitat, or Designated Outside Activity Area is
built or designated after an Oil and Gas Development Plan or Form 2A is
approved, the Operator of the Oil and Gas Location need not comply with Rule
423.c with respect to the newly built or designated Building Unit, High
Occupancy Building Unit, High Priority Habitat, or Designated Outside Activity
Area.
(9) Operators will maintain
records to demonstrate compliance with this Rule 423.c, and will submit the
records to the Director upon request.
d.
Cumulative Noise. All noise
measurements will be cumulative.
(1) Noise
measurements taken at noise points of compliance designated pursuant to Rule
423.a.(5) will take into account ambient noise, rather than solely the
incremental increase of noise from the facility targeted for
measurement.
(2) At new or
substantially modified Oil and Gas Locations where ambient noise levels at
noise points of compliance designated pursuant to Rule 423.a.(5) already exceed
the noise thresholds identified in Table 423-1, then Operators will be
considered in compliance with Rule 423, unless at any time their individual
noise contribution, measured pursuant to Rule 423.c, increases noise above
ambient levels by greater than 5 dBC and 5 dBA between 7:00 p.m. and 7:00 a.m.
or 7 dBC and 7 dBA between 7:00 a.m. and 7:00 p.m. This Rule 423.d.(2) does not
allow Operators to increase noise above the maximum cumulative noise thresholds
specified in Table 423-2 after the Commencement of Production
Operations.
(3) After the
Commencement of Production Operations, if ambient noise levels already exceed
the maximum permissible noise thresholds identified in Table 423-1, under no
circumstances will new Oil and Gas Operations or a significant modification to
an existing Oil and Gas Operations raise cumulative ambient noise above:
Table 423-2 - Maximum Cumulative Noise
Levels
|
LAND USE
|
7:00 am to next 7:00 pm
|
7:00 pm to next 7:00 am
|
|
Residential /Rural/State Parks/State Wildlife
Areas
|
65 db(A)
|
60 db(A)
|
|
Commercial/Agricultural
|
70 db(A)
|
65 db(A)
|
|
Light Industrial
|
80 db(A)
|
75 db(A)
|
|
Industrial
|
90 db(A)
|
85 db(A)
|
|
All Zones
|
75 db(C)
|
70 db(C)
|
e. If Oil and Gas Operations result in
persistent noise that adversely impacts public welfare, the Director may
require the Operator to take action pursuant to Rule 901.a.
