Appendix 6MARICOPA COUNTY

APPENDIX C

FUGITIVE DUST TEST METHODS

INDEX

SECTION 1

– [ RESERVED]

SECTION 2

– TEST METHODS FOR STABILIZATION

SECTION 3 – VISUAL OPACITY DETERMINATI ON OF EMISSIONS FROM DUSTGENERATING OPERATIONS

SECTION 4 – VISUAL OPACITY DETERMINA TION OF EMISSIONS FROM LIVESTOCK ACTIVITIES – CORRALS, PENS, AND ARENAS

C-1BLANK PAGE

C-2Adopted 06/16/99

Revised 02/16/00

Revised 04/07/04

Revised 03/26/08

MARICOPA COUNTY

AIR POLLUTION CONTROL REGULATIONS

APPENDIX C

FUGITIVE DUST TEST METHODS

1. [RESERVED]

2. TEST METHODS FOR STABILIZATION

2.1 For Unpaved Roads and Unpaved Parking Lots:

2.1.1 Opacity Test Method: The purpose of this test method is to estimate the percent opacity of fugitive dust plumes caused by vehicle movement on unpaved roads and unpaved parking lots. This method can only be conducted by an individual who has received certification as a qualified observer. Qualification and testing requirements can be found in Section 3.4 of this appendix.

a. Step 1: Stand at least 16.5 feet from the fugitive dust source in order to provide a clear view of the emissions with the sun oriented in the 140 ° sector to the back. Following the above requirements, make opacity observations so

that the line of vision is approximately perpendicular to the dust plume and wind direction. If multiple plumes ar e involved, do not include more than one plume in the line of sight at one time.

b. Step 2: Record the fugitive dust sour ce location, source type, method of control used, if any, observer's name, certification data and affiliation, and a sketch of the observer's position relative to the fugitive dust source. Also record the time, estimated distance to the fugitive dust source location, approximate wind direction, estimated wind speed, description of the sky condition (presence and color of clouds ), observer's position to the fugitive dust source, and color of the plume a nd type of background on the visible emission observation from both when op acity readings are initiated and completed.

c. Step 3: Make opacity observations, to the extent possible, using a contrasting background that is perpe ndicular to the line of vision. Make opacity observations approximately 1 meter above the surface from which the plume is generated. Note that the observation is to be made at only one visual point upon generation of a plume, as opposed to visually tracking the

C-3entire length of a dust plume as it is created along a surface. Make two observations per vehicle, beginning with the first reading at zero seconds and the second reading at five seconds . The zero-second observation should begin immediately after a plume has been created above the surface involved. Do not look continuously at the plume but, instead, observe the plume briefly at zero seconds a nd then again at five seconds.

d. Step 4: Record the opacity observations to the nearest 5% on an observational record sheet. Each momentary observation recorded represents the average opacity of emissions for a 5-s econd period. While it is not required by the test method, EPA recommends that the observer estimate the size of vehicles which generate dust plumes for which readings are taken (e.g. midsize passenger car or heavy-duty truc k) and the approximate speeds the vehicles are traveling when readings are taken.

e. Step 5: Repeat Step 3 (Section 2.1.1(c) of th is appendix) and Step 4 (Section 2.1.1(d) of this appendix) until you have recorded a total of 12 consecutive opacity readings. This will occur once six vehicles have driven on the source in your line of observation for which you are able to take proper readings. The 12 consecutive readings must be taken within the same period of

observation but must not exceed 1 hour. Observations immediately preceding and following interrupted observations can be considered

consecutive.

f. Step 6: Average the 12 opacity readings together. If the average opacity reading equals 20% or lower, the source is in compliance

2.1.2 Silt Content Test Method: The purpose of this test method is to estimate the silt content of the trafficked parts of unpaved roads and unpaved parking lots. The higher the silt content, the more fine dust particles that are released when cars and trucks drive on unpaved ro ads and unpaved parking lots.

a. Equipment:

(1) A set of sieves with the following openings: 4 millimeters (mm), 2 mm, 1 mm, 0.5 mm and 0.25 mm (or a set of standard/commonly available sieves), a lid, and collector pan.

(2) A small whisk broom or paintbrush w ith stiff bristles and dustpan 1 ft. in width. (The broom/brush should preferab ly have one, thin row of bristles no longer than 1.5 inches in length).

(3) A spatula without holes.

(4) A small scale with half-ounce incr ements (e.g., postal/package scale).

C-4(5) A shallow, lightweight container (e.g., plastic storage container).

(6) A sturdy cardboard box or other ri gid object with a level surface.

(7) A basic calculator.

(8) Cloth gloves (optional for handling metal sieves on hot, sunny days).

(9) Sealable plastic bags (if sendi ng samples to a laboratory).

(10) A pencil/pen and paper.

b. Step 1: Look for a routinely traveled surf ace, as evidenced by tire tracks. (Only collect samples from surfaces that are not damp due to precipitation or dew. This statement is not meant to be a standard in itself for dampness where watering is being used as a cont rol measure. It is only intended to ensure that surface testing is done in a representative manner.) Use caution when taking samples to ensure pers onal safety with respect to passing vehicles. Gently press the edge of a dustp an (1 foot in width) into the surface

four times to mark an area that is 1 square foot. Collect a sample of loose surface material using a whiskbroom or brush and slowly sweep the material into the dustpan, minimizing escape of dust particles. Use a spatula to lift heavier elements such as gravel. Only collect dirt/gravel to an approximate depth of 3/8 inch or 1 cm in the 1 square foot area. If you reach a hard, underlying subsurface that is < 3/8 inch in depth, do not continue collecting the sample by digging into the hard surface. In other words, you are only collecting a surface sample of loose material down to 1 cm. In order to confirm that samples are collected to 1 cm in depth, a wooden dowel or other similar narrow object at least one foot in length can be laid horizontally across the survey area while a metric ruler is held perpendicular

to the dowel.

At this point, you can choose to place th e sample collected into a plastic bag or container and take it to an independen t laboratory for silt content analysis. A reference to the procedure the laborato ry is required to follow is at the end

of this section.

c. Step 2 : Place a scale on a leve l surface. Place a lightwe ight container on the scale. Zero the scale with the weight of the empty container on it. Transfer the entire sample collected in the dustpan to the container, minimizing escape of dust particles. Weigh th e sample and record its weight.

d. Step 3: Stack a set of sieves in order acco rding to the size openings specified above, beginning with the largest size opening (4 mm) at the top. Place a collector pan underneath the bottom (0.25 mm) sieve.

C-5e. Step 4: Carefully pour the sample into the sieve stack, minimizing escape of dust particles by slowly brushing materi al into the stack with a whiskbroom or brush. (On windy days, use the trunk or door of a car as a wind barricade.) Cover the stack with a lid. Lift up th e sieve stack and shake it vigorously up, down and sideways for at least 1 minute.

f. Step 5 : Remove the lid from the stack and disassemble each sieve separately, beginning with the top sieve. As you remove each sieve, examine

it to make sure that all of the material has been sifted to the finest sieve through which it can pass (e.g., material in each sieve [besides the top sieve that captures a range of larger elements ] should look the same size). If this is not the case, re-stack the sieves and co llector pan, cover the stack with the lid, and shake it again for at least 1 mi nute. (You only need to reassemble the sieve(s) that contain material , which requires further sifting.)

g. Step 6 : After disassembling the sieves and collector pan, slowly sweep the material from the collector pan into th e empty container originally used to collect and weigh the entire sample. Take care to minimize escape of dust particles. You do not need to do anyt hing with material captured in the sieves; only the collector pan. Weigh the container with the material from the collector pan and record its weight.

h. Step 7 : If the source is an unpaved road, multiply the resulting weight by 0.38. If the source is an unpaved parki ng lot, multiply the resulting weight by 0.55. The resulting number is the estim ated silt loading. Then, divide by the total weight of the sample you re corded earlier in Step 2 (Section 2.1.2(c) of this appendix) and multiply by 100 to estimate the percent silt

content.

i. Step 8 : Select another two routinely travel ed portions of the unpaved road or unpaved parking lot and repeat this test method. Once you have calculated the silt loading and percent silt content of the 3 samples collected, average your results together.

j. Step 9: Examine results. If the average silt loading is less than 0.33 oz/ft2, the surface is STABLE. If the average silt loading is greater than or equal to 0.33 oz/ft2, then proceed to examine the average percent silt content. If the source is an unpaved road and the average percent silt content is 6% or less,

the surface is STABLE. If the source is an unpaved parking lot and the average percent silt content is 8% or less, the surface is STABLE. If your

field test results are within 2% of the standard (for example, 4%–8% silt content on an unpaved road), it is re commended that you collect 3 additionalsamples from the source according to Step 1 (Section 2.1.2(b) of this appendix) and take them to an independent laboratory for silt content analysis.

C-6k. Independent Laboratory Analysis: You may choose to collect 3 samples from the source, according to Step 1 (Section 2.1.2(b) of this appendix), and send them to an independent laboratory for silt content analysis rather than conduct the sieve field procedure. If so, the test method the laboratory is required to use is: U.S. Environmen tal Protection Agency (1995), “Procedures for Laboratory Analysis of Surface/Bulk Dust Loading Samples”, (AP-42 Fifth Edition, Volume I, Appe ndix C.2.3 “Silt Analysis”), Office of Air Quality Planning and Standards, Research Triangle Park, North

Carolina.

2.2 Stabilization Limitations for Open Areas and Vacant Lots: The test methods described in Section 2.3 through Section 2.7 ofthis appendix shall be used to determine whether an open area or a vacant lot has a stabilized surface. Should a disturbed open area or vacant lot contain more than one type of disturbance, soil, vegetation, or other characteristics, which are visibly disti nguishable, test each representative surface separately for stability, in an area that represents a random po rtion of the overall disturbed conditions of the site, according to the appropriate test methods in Section 2.3 through Section 2.7 of this appendix.

2.3 Soil Crust Determinatio n (the Drop Ball Test):

2.3.1 Drop a steel ball with a diameter of 15.9 millimeters (0.625 inches) and a mass ranging from 16-17 grams (0.56-0.60 ounce) from a distance of one foot directly above (at a 90 ° angle perpendicula r to) the soil surface. If blowsand is present, clear the blowsand from the surfaces on which the drop ball test is

conducted. Blowsand is defined as thin deposits of loose uncombined grains covering less than 50% of a vacant lot or project site that have not originated from the representative surface being teste d. If material covers a visible crust, which is not blowsand, apply the test me thod in Section 2.4: Determination of Threshold Friction Velocity (TFV) of this appendix to the loose material to

determine whether the surface is stabilized.

2.3.2 A sufficient crust is defined under th e following conditions: once a ball has been dropped according to Section 2.3.1 of this appendix, the ball does not sink into the surface, so that it is partia lly or fully surrounded by loose grains and, upon removing the ball, the surface upon wh ich it fell has not been pulverized, so that loose grains are visible.

2.3.3 Randomly select each representative di sturbed surface for the drop ball test by using a blind “over the s houlder” toss of a throwable object (e.g., a metal weight with survey tape attached). Using the point of fall as the lower left-hand corner, measure a one-foot square area . Drop the ball three times within the one-foot by one-foot square survey area, using a consistent pattern across the survey area. The survey area shall be considered to have passed the drop ball test if at least two out of the three times that the ball was dropped, the results

met the criteria in Sectio n 2.3.2 of this appendix. Se lect at least two other

C-7survey areas that represent a random por tion of the overall di sturbed conditions of the site, and repeat this procedure. If th e results meet the criteria of Section 2.3.2 of this appendix for all of the survey areas tested, then the site shall be considered to have passed the drop ball te st and shall be considered sufficiently

crusted.

2.3.4 At any given site, the exis tence of a sufficient crust covering one portion of the site may not represent th e existence or protective ness of a crust on another portion of the site. Repeat the drop ball test as often as necessary on each portion of the overall conditi ons of the site using the random selection method

set forth in Section 2.3.3 of this appendix for an accurate assessment.

2.4 Determination of Threshold Friction Velocity (TFV): For disturbed surface areas that are not crusted or vegetated, determine threshold friction velocity (TFV) according to the following sieving field procedure (based on a 1952 laboratory procedure published by W. S. Chepil).

2.4.1 Obtain and stack a set of sieves with the following openings: 4 millimeters (mm), 2 mm, 1 mm, 0.5 mm, and 0.25 mm or obtain and stack a set of standard/commonly available sieves. Place the sieves in order according to size openings, beginning with the largest size opening at th e top. Place a collector pan underneath the bottom (0.25 mm) sieve. Collect a sample of loose surface material from an area at least 30 cm by 30 cm in size to a depth of approximately 1 cm using a brush and dustpan or other similar device. Only collect soil samples from dry surfaces (i.e., when the surface is not damp to the touch). Remove any rocks larger than 1 cm in diameter from the sample. Pour the sample into the top sieve (4-mm ope ning) and cover the sieve/collector pan unit with a lid. Minimize escape of partic les into the air when transferring surface soil into the sieve/collector pan unit. Move the covered sieve/collector pan unit by hand using a broad, circular arm motion in the horizontal plane. Complete twenty circular arm moveme nts, ten clockwise and ten counterclockwise, at a speed just necessary to achieve some relative horizontal motion between the sieves and the particles. Re move the lid from the sieve/collector pan unit and disassemble each sieve separa tely beginning with the largest sieve. As each sieve is removed, examine it for l oose particles. If lo ose particles have not been sifted to the finest sieve through which they can pass, reassemble and cover the sieve/collector pan unit and ge ntly rotate it an additional ten times. After disassembling the sieve/collector pan unit, slightly tilt and gently tap each sieve and the collector pan so that mate rial aligns along one side. In doing so, minimize escape of particles into the air. Line up the sieves and collector pan in a row and visibly inspect the relative qua ntities of catch in order to determine which sieve (or whether the collector pa n) contains the greatest volume of

material. If a visual determination of relative volumes of catch among sieves is difficult, use a graduated cylinder to m easure the volume. Estimate TFV for the sieve catch with the greatest volume using Table 1 of this appendix, which provides a correlation between sieve opening size and TFV.

C-8Table 1. Determination of Threshold Friction Velocity Tyler Sieve No. ASTM 11 Sieve No. Opening (mm) TFV(cm/s)

5 5 4 135

9 10 2 100

16 18 1 76

32 35 0.5 58

60 60 0.25 43

Collector Pan

⎯ ⎯ 30

2.4.2 Collect at least three so il samples which represent random portions of the overall conditions of the site, repeat the ab ove TFV test method for each sample and average the resulting TFVs together to determine the TFV uncorrected for nonerodible elements. Non-erodible elements are distinct elements, in the random portion of the overall conditi ons of the site, that are larger than 1 cm in diameter, remain firmly in place duri ng a wind episode, and inhibit soil loss by consuming part of the shear stress of the wind. Non-erodible elements include

stones and bulk surface material but do not include flat or standing vegetation. For surfaces with non-erodible elements, determine corrections to the TFV by identifying the fraction of the survey area, as viewed from directly overhead, that is occupied by non-erodible elements using the following procedure. For a more detailed description of this pro cedure, see Section 2.7 (Test Methods for Stabilization-Rock Test Method) of this appendix. Select a survey area of 1 meter by 1 meter that represents a rando m portion of the overall conditions of the site. Where many non-erodible elements lie within the survey area, separate the non-erodible elements into groups according to size. For each group,

calculate the overhead area for the no n-erodible elements according to the following equations:

Average Length × Average Width = Average Dimensions Eq. 1

Average Dimensions × Number of Elements = Overhead Area Eq. 2

Overhead Area of Group 1 + Overhead Area of Group 2 (etc.) = Total Overhead Area Eq. 3

Total Overhead Area ÷ 2 = Total Frontal Area Eq. 4

(Total Frontal Area ÷ Survey Area) × 100 = Percent Cover of Non-Erodible Elements Eq. 5

Note: Ensure consistent units of measurem ent (e.g., square meters or square inches) when calculating percent cover.

Repeat this procedure on an additional two distinct survey areas that represent a random portion of the overall conditions of the site and average the results. Use Table 2 of this appendix to identify the correction factor for the percent cover of non-erodible elements. Multiply the TFV by the corresponding correction

factor to calculate the TFV corrected for non-erodible elements.

C-9Table 2. Correction Factors for Threshold Friction Velocity

Percent Cover of Non-Erodible Elements Factor Correction

Factor Greater than or equal to 10% 5 Greater than or equal to 5% and less than 10% 3 Less than 5% and greater than or equal to 1% 2

Less than 1% None

2.5 Determination of Fl at Vegetative Cover : Flat vegetation incl udes attached (rooted) vegetation or unattached vegetative debris lying on the surface with a predominant horizontal orientation that is not subject to movement by wind. Flat vegetation, which is dead but firmly attached, shall be cons idered equally protective as live vegetation. Stones or other aggregate larg er than 1 centimeter in diameter shall be considered protective cover in the course of conducting the line transe ct test method. Where flat vegetation exists, conduct the foll owing line transect test method.

2.5.1 Line Transect Test Method : Stretch a 100-foot measur ing tape across a survey area that represents a random portion of the overall conditions of the site. Firmly anchor both ends of the measuri ng tape into the su rface using a tool such as a screwdriver, with the tape stre tched taut and close to the soil surface. If vegetation exists in regular rows, place the tape diagonally (at approximately

a 45 ° angle) away from a parallel or perpendicular position to the vegetated rows. Pinpoint an area the size of a 3/32 inch diameter brazing rod or wooden

dowel centered above each 1-foot interv al mark along one edge of the tape.

Count the number of times that flat vegetation lies directly underneath the pinpointed area at 1-foot intervals. Cons istently observe th e underlying surface

from a 90 ° angle directly above each pinpoint on one side of the tape. Do not count the underlying surface as vegetated if any portion of the pinpoint extends beyond the edge of the vegetation undernea th in any directio n. If clumps of vegetation or vegetative de bris lie underneath the pinpointed area, count the surface as vegetated, unless bare soil is visible directly below the pinpointed area. When 100 observations have been made, add together the number of times a surface was counted as vege tated. This total represen ts the percent of flat vegetation cover (e.g., if 35 positive counts were made, then vegetation cover is 35%). If the survey area that represen ts a random portion of the overall conditions of the site is too sm all for 100 observations, make as many observations as possible. Then multiply the count of vegetated surface areas by the appropriate conversion factor to obtain percent c over. For example, if vegetation was counted 20 times within a total of 50 observations, divide 20 by 50 and multiply by 100 to obtain a flat vegetation cover of 40%.

2.5.2 Conduct the line transect test method, as described in Section 2.5.1 of this appendix, an additional two times on areas that represent a random portion of

the overall conditions of the site and average results.

C-102.6 Determination of Standing Vegetative Cover: Standing vegetation includes vegetation that is attached (rooted) with a predominant ve rtical orientation. Standing vegetation, which is dead but firmly rooted, shall be considered equally protective as live vegetation. Conduct the following standing vegetation test method to determine if 30% cover or more exists. If the resulting per cent cover is less than 30% but equal to or greater than 10%, then conduc t the test in Section 2.4 (D etermination of Threshold Friction Velocity [TFV]) of this appendix in order to determine if the site is stabilized, such that the standing vegetation cover is eq ual to or greater than 10%, where threshold friction velocity, corrected fo r non-erodible elements, is e qual to or greater than 43

cm/second.

2.6.1 For standing vegetation that consists of large, separate vegetative structures (e.g., shrubs and sagebrush), select a survey area that represents a random portion of the overall conditions of the site that is the shape of a square with sides equal to at least 10 times the aver age height of the ve getative structures. For smaller standing vegetation, select a su rvey area of three feet by three feet.

2.6.2 Count the number of standing vegetativ e structures within the survey area. Count vegetation, which grows in clumps as a single unit. Where different types of vegetation exist and/or vegetati on of different height and width exists, separate the vegeta tive structures with similar dimensions into groups. Count the number of vegetative structures in each group within the survey area. Select an individual structure within each group th at represents the average height and width of the vegetation in the group. If the structure is dense (e.g., when looking at it vertically from base to top there is little or ze ro open air space within its perimeter), calculate and reco rd its frontal silhouette area, according to Equation 6 of this appendix. Also, use Equation 6 of this appendix to estimate the average height and width of the vegetation if the survey area is larger than nine square feet. Otherwis e, use the procedure in Section 2.6.3 of this appendix to calculate the frontal s ilhouette area. Then ca lculate the percent cover of standing vegetation accordi ng to Equations 7, 8, and 9 of this appendix.

Average Height × Average Width = Frontal Silhouette Area Eq. 6

Frontal Silhouette Area of Individual Vegetative Structure × Number of Vegetation Structures Per Group = Frontal Silhouette Area of Group Eq. 7

Frontal Silhouette Area of Group 1 + Frontal Silhouette Area of Group 2 (etc.)

= Total Frontal Silhouette Area. Eq. 8

(Total Frontal Silhouette Area ÷ Survey Area) × 100 = Percent Cover of Standing Vegetation Eq. 9

[(Number of Circled Gridlines within the Outlined Area Counted that are not Covered by Vegetation ÷ Total Number of Gridline Intersections within the Outlined Area) × 100] = Percent Open Space Eq. 10

100 – Percent Open Space = Percent Vegetative Density Eq. 11

C-11Percent Vegetative Density ÷ 100 = Vegetative Density Eq. 12

Max. Height × Max. Width × (Vegetative Density ÷ 0.4) 0.5 = Frontal Silhouette Area Eq. 13

Note: Ensure consistent units of measurem ent (e.g., square meters or square inches) when calculating percent cover.

2.6.3 Vegetative Density Factor: Cut a single, representative piece of vegetation (or consolidated vegetative structure) to w ithin 1 cm of surface soil. Using a white paper grid or transparent grid over white paper, lay the vegetation flat on top of the grid (but do not apply pressure to fl atten the structure). Grid boxes of 1-inch or 1⁄2-inch squares are sufficient for most vegetation when conducting this procedure. Using a marker or pencil, outline the shape of the vegetation alongits outer perimeter, according to Figure B, C, or D of this appendix, as appropriate. (Note: Figure C differs from Fi gure D primarily in that the width of vegetation in Figure C is narrow at its base and gradually broadens to its tallest height. In Figure D, the width of th e vegetation generally becomes narrower from its midpoint to its ta llest height.) Remove the ve getation, count and record the total number of gridline intersecti ons within the outlin ed area, but do not count gridline intersections that connect with the outli ned shape. There must be at least 10 gridline intersections within the outlined area and preferably more than 20, otherwise, use smaller grid boxes. Draw small circles (no greater than a 3/32-inch diameter) at each gridline in tersection counted within the outlined area. Replace the vegetation on the grid within its outlined shape. From a distance of approximately 2 feet directly above the grid, observe each circled gridline intersection. Co unt and record the numbe r of circled gridline intersections that are not covered by a ny piece of the vegetation. To calculate percent vegetative density, use Equations 10 and 11 of this appendix. If percent vegetative density is equal to or greate r than 30, use an equation (one of the Equations 14, 15, or 16 of this appendix) that matches the outline used to trace the vegetation (Figure B, C, or D) to cal culate its frontal silhouette area. If percent vegetative density is less th an 30, use Equations 12 and 13 of this appendix to calculate the frontal silhouette area.

Figure B. Cylinder

Frontal Silhouette Area = Maximum Height × Maximum Width Eq. 14

C-12Figure C. Inverted Cone

Frontal Silhouette Area = Maximum Height × 1⁄2 Maximum Width Eq. 15

Figure D. Upper Sphere

Frontal Silhouette Area = (3.14 × Maximum Height × 1⁄2 Maximum Width) ÷ 2 Eq. 16

2.7 Rock Test Method: The Rock Test Method, which is similar to Section 2.4 (Test Methods for Stabilization-Determination of Threshold Friction Velocity [TFV]) of thisappendix, examines the wind-resistance effects of rocks and other non-erodible elements on disturbed surfaces. Non-erodible elem ents are objects larger than 1 centimeter (cm) in diameter that remain firmly in place even on windy days. Typically, nonerodible elements include rocks, stones, gl ass fragments, and hard-packed clumps of soil lying on or embedded in the surface. Vegetation does not count as a non-erodible element in this method. The purpose of this test method is to estimate the percent cover of non-erodible elements on a given surface to see whether such elements take up enough space to offer protection against windblown dust. For simplification, the following test method refers to all non-erodible elements as “rocks”.

2.7.1 Select a 1-meter × 1-meter survey ar ea that represents the general rock distribution on the surface. (A 1-meter × 1-meter area is slightly greater than a 3-foot × 3-foot area). Mark off the survey area by tracing a straight, visible line in the dirt along the edge of a measuri ng tape or by placing short ropes, yard sticks, or other straight objects in a square around the survey area.

2.7.2 Without moving any of the rocks or ot her elements, examine the survey area.

Since rocks > 3/8 inch (1 cm) in diameter are of interest, measure the diameter of some of the smaller rocks to a ge t a sense for which rocks need to be

considered.

C-132.7.3 Mentally group the rocks > 3/8 inch (1 cm) diameter lying in the survey area into small, medium, and large size categor ies. Or, if the ro cks are all approximately the same size, simply select a rock of average size and typical shape. Without removing any of the rocks from the ground, count the number of rocks in the survey area in each group a nd write down the resulting number.

2.7.4 Without removing rocks, select one or two average-size rocks in each group and measure the length and width. Use eith er metric units or standard units. Using a calculator, multiply the length tim es the width of the rocks to get the average dimensions of the rocks in ea ch group. Write down the results for each rock group.

2.7.5 For each rock group, multiply the average dimensions (length times width) by the number of rocks counted in the group. Add the results from each rock group to get the total rock area within the survey area.

2.7.6 Divide the total rock area, calculated in Section 2.7.5 of this appendix, by two (to get frontal area). Divide the resul ting number by the size of the survey area (making sure the units of measurement match), and multiply by 100 for percent rock cover. For example, th e total rock area is 1,400 square centimeters, divide 1,400 by 2 to get 700. Divide 700 by 10,000 (the survey area is 1 meter by 1 meter, which is 100 centimeters by 100 centimeters or 10,000 square centimeters), and multiply by 100. The result is 7% rock cover. If rock measurements are made in inches, convert the survey area from meters to inches (1 inch = 2.54 centimeters).

2.7.7 Select and mark off two additional survey areas and repeat the procedures described in Sections 2.7.1 through 2. 7.6 of this appendix. Make sure the additional survey areas also represent th e general rock distribution on the site. Average the percent cover results from all three survey areas to estimate the average percent of rock cover.

2.7.8 If the average rock cover is greater than or equal to 10%, the surface is stable. If the average rock cover is less than 10 %, follow the procedures in Section 2.7.9 of this appendix.

2.7.9 If the average rock cover is less than 10%, the surface may or may not be stable. Follow the procedures in Se ction 2.4 (Determination of Threshold Friction Velocity [TFV]) of this rule and use the results from the rock test method as a correction (i.e., multiplication) factor. If the rock cover is at least 1%, such rock cover helps to limit wi ndblown dust. However, depending on the soil’s ability to release fine dust particle s into the air, the percent rock cover may or may not be sufficient enough to stab ilize the surface. It is also possible

that the soil itself has a high enough TFV to be stable without even accounting

for rock cover.

C-142.7.10 After completing the procedures desc ribed in Section 2.7.9 of this appendix, use Table 2 of this appendix to identify the appropriate correction factor to the TFV, depending on the percent rock cover. Multiply the correction factor by the

TFV value for a final TFV estimate that is corrected for non-erodible elements.

3. VISUAL OPACITY DETERMINAT ION OF EMISSIONS FROM DUSTGENERATING OPERATIONS

3.1 Applicability: This method is applicable for the determination of opacity of fugitive dust plumes from dust-generating operations.

3.2 Principle: the opacity of emissions from sources of visible emissions is determined visually by an observer qualified according to the procedures of Section 3.4 of this appendix.

3.3 Procedures: An observer qualified in accordance with Section 3.4 of this appendix, shall use the following procedures for visua lly determining the opacity of emissions.

3.3.1 To determine the opacity of non-con tinuous dust plumes caused by activities including, but not limited to, bul k material loading/unloading, nonconveyorized screening, or trenching with backhoes:

a. Position: Stand at least 25 feet from th e dust-generating operation in order to provide a clear view of the emissi ons with the sun oriented in the 140o

sector to the back. Choose a discrete portion of the operation for observation, such as the unloading point, not th e whole operation. Following the above requirements, make opacity observations so that the line of vision is approximately perpendicular to the dust pl ume and wind direction. If multiple plumes are involved, do not include more than one plume in the line of sight

at one time.

b. Initial Fallout Zone: The initial fallout zone within the plume must be identified. Record the distance from the equipment or path that is your

identified initial fallout zone. The initial fallout zone is that area where the heaviest particles drop out of the en trained fugitive dust plume. Opacity readings should be taken at the maximum point of the entrained fugitive dust plume that is located outside the initial fallout zone.

c. Field Records: Note the following on an observational r ecord sheet:

(1) Location of dust-generating opera tion, type of operation, type of equipment in use and activity, and method of control used, if any;

(2) Observer's name, certification data and affiliation, a sketch of the observer's position relative to th e dust-generating operation, and

C-15observer’s estimated distance and dir ection to the location of the dustgenerating operation;

(3) Time that readings begin, appr oximate wind direction, estimated wind speed, description of the sky conditi on (presence and color of clouds);

and

(4) Color of the plume and type of background.

d. Observations: Make opacity observations, to the extent possible, using a contrasting background that is perpendi cular to the line of vision. Make two observations per discrete activity, beginning with the first reading at zero seconds and the second reading at fi ve seconds. The zero-second observation should begin immediately after a plume has been created above the surface involved. Do not look continuously at the plume but, instead, observe the plume briefly at zero seconds and then again at five seconds.

e. Recording Observations: Record the opacity observations to the nearest

5% on an observational record sheet. Each momentary observation recorded represents the average op acity of emissions for a five-second period. Repeat observations until you have recorded at least a total of 12 consecutive opacity readings. The 12 consecutive read ings must be taken within the same period of observation but must not exceed one hour. Observations immediately preceding and following interrupted observations can be considered consecutive (e.g., vehicle traveled in front of path, plume doubled over).

f. Data Reduction: Average 12 consecutive opacity readings together. If the average opacity reading equals 20% or lower, the dust-generating operation is in compliance.

3.3.2 To determine the opacity of continuous dust plumes caused by equipment and activities including but not limited to graders, trenchers, paddlewheels, blades, clearing, leveling, and raking:

a. Position: Stand at least 25 feet from the dust-generating operation to provide

a clear view of the emissions with the s un oriented in the 140o sector to your back. Following the above requirements, make opacity observations so that the line of vision is approximately perpendicular to the dust plume and wind

direction.

b. Dust Plume: Evaluate the dust plume gene ration and determine if the observations will be made from a single plume or from multiple related plumes.

C-16(1) If a single piece of equipment is observed working, then all measurements should be taken off the resultant plume as long as the equipment

remains within the 140o sector to the back.

(2) If there are multiple related sources or multiple related points of emissions of dust from a particular activity, or multiple pieces of equipment operating in a confined area, opacity readings should be taken at the densest point within the discrete length of equipment travel path

within the 140o sector to the back. Readings can be taken for more than one piece of equipment within the discre te length of travel path within

the 140o sector to the back.

c. Initial Fallout Zone: The initial fallout zone within the plume must be identified. Record the distance from the equipment or path that is your

identified initial fallout zone. The initial fallout zone is that area where the heaviest particles drop out of the en trained fugitive dust plume. Opacity readings should be taken at the maximum point of the entrained fugitive dust plume that is located outside the initial fallout zone.

d. Field Records: Note the following on an observational r ecord sheet:

(1) Location of the dust-generating opera tion, type of operation, type of equipment in use and activity, and method of control used, if any;

(2) Observer's name, certification data and affiliation, a sketch of the observer's position relative to th e dust-generating operation, and

observer’s estimated distance and dir ection to the location of the dustgenerating operation; and

(3) Time that readings begin, appr oximate wind direction, estimated wind speed, description of the sky condition (presence and color of clouds).

e. Observations: Make opacity observations, to the extent possible, using a contrasting background that is perpe ndicular to the line of vision. Make opacity observations at a point beyon d the fallout zone. The observations should be made at the densest point. Observations will be made every 10

seconds until at least 12 readings have been recorded. Do not look continuously at the plume, but observe the plume momentar ily at 10-second intervals. If the equipment generating the plume travels outside the field of observation or if the equipment ceases to operate, mark an “X” for the 10- second reading interval. Mark an “X” when plumes are stacked or doubled, either behind or in front, or become pa rallel to line of si ght. Opacity readings identified as “X” shall be considered interrupted readings.

C-17f. Recording Observations: Record the opacity observations to the nearest

5% on an observational record sheet. Each momentary observation recorded represents the average opacity of emissions for a 10-second period.

g. Data Reduction: Average 12 consecutive opacity readings together. If the average opacity reading equals 20% or lower, the dust-generating operation is in compliance.

3.4 Qualification and Testing:

3.4.1 Certification Requirements: To receive certification as a qualified observer, a

candidate must be tested and demonstrat e the ability to assign opacity readings

in 5% increments to 25 different blac k plumes and 25 different white plumes,

with an error not to ex ceed 15% opacity on any one reading and an average error not to exceed 7.5% opac ity in each category. Candidates shall be tested according to the procedures described in Section 3.4.2 of this appendix. Any smoke generator used pursuant to Se ction 3.4.2 of this appendix shall be equipped with a smoke meter which meet s the requirements of Section 3.4.3 of this appendix. Certification tests that do not meet the requirements of Sections 3.4.2 and 3.4.3 of this appendix are not vali d. The certification shall be valid for a period of 6 months, and after each 6-month period the qualification procedures must be repeated by an obse rver in order to re tain certification.

3.4.2 Certification Procedure: The certification test c onsists of showing the candidate a complete run of 50 plumes , 25 black plumes and 25 white plumes, generated by a smoke generator. Plumes shall be presented in random order

within each set of 25 black and 25 wh ite plumes. The candidate assigns an opacity value to each plume and records the observation on a suitable form. At the completion of each run of 50 readi ngs, the score of the candidate is determined. If a candidate fails to qualif y, the complete run of 50 readings must be repeated in any retest. The smoke te st may be administered as part of a smoke school or training program, and may be preceded by training or familiarization runs of the smoke generator, during which candidates are shown black and white plumes of known opacity.

3.4.3 Smoke Generator Specifications: Any smoke generator us ed for the purpose of Section 3.4.2 of this appendix shall be equipped with a smoke meter installed to measure opacity across the diameter of the smoke generator stack. The smoke meter output shall display in-st ack opacity, based upon a path length equal to the stack exit diameter on a full 0% to 100% chart recorder scale. The smoke meter optical design and perfor mance shall meet the specifications shown in Table 3 of this appendix. Th e smoke meter shall be calibrated as prescribed in Section 3.4.3(a) of this appendix prior to conducting each smoke reading test. At the completion of each te st, the zero and span drift shall be checked, and if the drift exceeds plus or minus 1% opacity, the condition shall be corrected prior to co nducting any subsequent te st runs. The smoke meter

C-18shall be demonstrated, at the time of installation, to meet the specifications listed in Table 3 of this appendix. This demonstration shall be repeated following any subsequent repair or repla cement of the photocell or associated electronic circuitry, including the chart r ecorder or output meter, or every 6 months, whichever occurs first.

a. Calibration: The smoke meter is calibrated after allowing a minimum of 30 minutes warm-up by alternately produc ing simulated opacity of 0% and 100%. When stable response at 0% or 100% is noted, the smoke meter is adjusted to produce an output of 0% or 100%, as appropriate. This calibration shall be repeated until stable 0% and 100% readings are produced without adjustment. Simulated 0% a nd 100% opacity values may be produced by alternately switching the powe r to the light source on and off while the smoke generator is not producing smoke.

b. Smoke Meter Evaluation: The smoke meter design and performance are to

be evaluated as follows:

(1) Light Source: Verify, from manufacturer's data and from voltage measurements made at the lamp, as installed, that the lamp is operated within plus or minus 5% of the nominal rated voltage.

(2) Spectral Response of Photocell: Verify from manufacturer's data that the photocell has a photopic response (i.e., the spectr al sensitivity of the cell shall closely approximate the sta ndard spectral-luminosity curve for photopic vision which is referenced in (b) of Table 3 of this appendix).

(3) Angle of View: Check construction geometry to ensure that the total angle of view of the smoke plume, as seen by the photocell, does not

exceed 15 ° . Calculate the tota l angle of view ( φ v ) as follows:

Total Angle of View = 2 tan -1 (d/2L)

where: d = The photocell diameter + the diam eter of the limiting aperture; and L = The distance from the photocell to the limiting aperture. The limiting aperture is the point in th e path between the photocell and the smoke plume where the angle of view is most restricted. In smoke generator smoke meters, this is normally an orifice plate.

(4) Angle of Projection: Check construction geometry to ensure that the total angle of projection of the lamp on the smoke plume does not exceed

15 ° . Calculate the total angle of projection ( φ p ) as follows:

Total Angle of Projection = 2 tan -1 (d/2L)

C-19where: d = The sum of the length of the la mp filament + the diameter of the limiting aperture; and L = The distance from the lamp to the limiting aperture.

(5) Calibration Error: Using neutral-density filters of known opacity,

check the error between the actual response and the theoretical linear response of the smoke meter. This check is accomplished by first calibrating the smoke meter, accord ing to Section 3.4.3(a) of this appendix, and then inserting a series of three neutral-density filters of nominal opacity of 20%, 50%, and 75% in the smoke meter path length. Use filters calibrated within plus or minus 2%. Care should be taken when inserting the filters to prevent stray light from affecting the meter.

Make a total of five nonconsecutive readings for each filter. The maximum opacity error on any one read ing shall be plus or minus 3%.

(6) Zero and Span Drift: Determine the zero and span drift by calibrating and operating the smoke generator in a normal manner over a 1-hour period. The drift is measured by checking the zero and span at the end of this period.

(7) Response Time: Determine the response time by producing the series of five simulated 0% and 100% opaci ty values and observing the time required to reach stable response. Opacity values of 0% and 100% may be simulated by alternately switching the power to the light source off and on while the smoke ge nerator is not operating.

Table 3. Smoke Meter Design a nd Performance Specifications

Parameter Specification a. Light source Incandescent lamp operated at nominal rated voltage. b. Spectral response of photocell Photopic (daylight spectral re sponse of the human eye) c. Angle of view 15 ° maximum total angle d. Angle of projection 15 ° maximum total angle

e. Calibration error Plus or minus 3% opacity, maximum f. Zero and span drift Plus or minus 1% opacity, 30 minutes g. Response time Less than or equal to 5 seconds

4. VISUAL OPACITY DETERMINATION OF EMISSIONS FROM LIVESTOCK ACTIVITIES – CORRALS, PENS, AND ARENAS

4.1 Applicability: This method is applicable for the determination of opacity of fugitive dust plumes from livestock activit ies (corrals, pens, and arenas).

4.2 Principle: The opacity of emissions from lives tock activities (corrals, pens, and arenas) is determined visually by an observe r qualified according to Section 3.4 of this appendix.

C-20C-21 4.3 Procedures: An observer qualified in accordance with Section 3.4 of this appendix, shall use the following procedures for visua lly determining the opacity of emissions:

4.3.1 Position: Stand at a position at least 5 meters from the livestock activities (corrals, pens, and arenas) in order to pr ovide a clear view of the emissions with

the sun oriented in the 140 ° sector to the back. Consistent as much as possible with maintaining the above requirements, make opacity observations from a position such that the line of sight is approximately perpendicular to the plume and wind direction. As much as possible, if multiple plumes are involved, do not include more than one plume in the line of sight at one time.

4.3.2 Field Records: Record the name of the site, method of control used, if any, observer's name, certification data and affiliation, and a sketch of the observer's position relative to the livestock activity (corrals, pens, and arenas). Also, record the time, estimated distance to th e livestock activity (corrals, pens, and arenas) location, approximate wind direc tion, estimated wind speed, description of the sky condition (presence and color of clouds), observer's position relative to the livestock activity (corrals, pens, and arenas), and color of the plume and type of background on the visible emi ssion observation from when opacity readings are initiated and completed.

4.3.3 Observations: Make opacity observations, to the extent possible, using a contrasting background. Fo r storage piles, make opacity observations approximately 1 meter above the surface from which the plume is generated. The initial observation should begin imme diately after a plume has been created

above the surface involved. Do not look con tinuously at the plume, but instead observe the plume momentarily at 15-second intervals.

4.3.4 Recording Observations: Record the opacity observations to the nearest 5% every 15 seconds on an observational record sheet. If a multiple plume exists at the time of an observation, do not record an opacity reading. Mark an “X” for that reading. If the livestock activ ity (corrals, pens, and arenas) ceases operating, mark an “X” for the 15-second interval reading. Re adings identified as “X” shall be considered interrupted readings.

4.3.5 Data Reduction: Within any 60-minute period, c ount at least three minutes that are greater than 20% opacity. If at least 13 readings are greater than 20% opacity, the livestock activity (corrals, pens, and arenas) is not in compliance. Readings immediately preceding and follo wing interrupted readings shall be

deemed consecutive and in no case shall two sets overlap, resulting in multiple

violations.BLANK PAGE

C-22