UNIFORM PLACEMENT OF PERCOLATION TESTS
Uniform Placement of Percolation Tests
N.J.A.C. 7:9A-6.1(e)7 of these standards requires that percolation tests be spaced uniformly within the area of the disposal field. Acceptable patterns or arrangements for percolation test placement depend upon the size and shape of the disposal field as outlined below. Patterns other than those provided below may be approved provided that it is determined by the Administrative Authority that the test results submitted are representative of the soil conditions throughout the entire area of the disposal field.
Definitions
The following words and terms shall have the following meanings when used within Appendix B of this chapter:
"Center" means the intersection of the two disposal field diagonals.
"Diagonal" means a line connecting opposite corners of the disposal field.
"Elongated disposal field" means a disposal field with a length/width ratio of 3.0-5.0.
"End" means one of the two shorter sides in a disposal field which has a length/width ratio not equal to 1.0.
"Length" means the longest dimension of the disposal field, or the distance between the ends of the disposal field.
"Long axis" means a line connecting the midpoints of the disposal field ends.
"Rectangular disposal field" means a disposal field with a length/width ratio of 1.5-3.0.
"Side" means one of the two longer sides of a disposal field which has a length/width ratio not equal to 1.0.
"Square disposal field" means a disposal field with a length/width ratio of 1.0-1.5.
"Very elongated disposal field" means a disposal field with a length/width ratio greater than 5.0.
"Width" means the shortest dimension of the disposal field, or the distance between the sides of the disposal field.
A. When the disposal field is less than 1500 square feet, a minimum of two percolation tests are required and the following arrangements are acceptable: All Disposal Field Shapes
1. Both tests spaced along the long axis of the field, the minimum distance between tests one third of the length of the field.2. Both tests spaced along the diagonal of the field, the minimum distance between tests one third the length of the diagonal.B. When the disposal field size is 1500 to 3000 square feet, a minimum of three percolation tests are required and the following arrangements are acceptable: All Disposal Field Shapes
1. All tests spaced evenly along the diagonal of the field, the minimum distance between tests one quarter the length of the diagonal.2. One test near the midpoint of a side, one test near each of the two opposite corners. Field Shape Rectangular to Very Elongated (L/W [GREATER THAN] 1.5)
3. All three tests spaced evenly along the long axis; minimum distance between tests one quarter the length of the disposal field.C. When the disposal field size is 3000 to 4500 square feet, a minimum of four percolation tests are required and the following arrangements are acceptable: Field Shape Square to Rectangular (L/W = 1.0 - 3.0)
1. One test near the midpoint of each of the sides and ends.2. One test near each of the four corners. All Field Shapes
3. A zig-zag pattern with tests placed at points along one side which are approximately zero thirds and two thirds the distance from end to end, and along the opposite side at points which are approximately one third and three thirds the distance from end to end. Field Shape Elongated to Very Elongated (L/W [GREATER THAN] 3.0)
4. All tests spaced evenly along the long axis of the field, the minimum distance between tests one fifth the length of the field.5. All tests spaced evenly along the diagonal of the field, the minimum distance between tests one fifth the length of the diagonals.D. When the disposal field size exceeds 4500 square feet, a minimum of five percolation tests are required and the following arrangements are acceptable: Square Fields
1. One test near the midpoints of each of the sides and ends, one test near the center of the field. Field Shape Square to Rectangular (L/W = 1.0 - 3.0)
2. One test near each corner of the field, one test near the center of the field. All Field Shapes
3. A zig-zag pattern with tests placed at points along one side which are approximately zero fourths, two fourths and four fourths the distance from end to end, and along the opposite side at points which are approximately one fourth and three fourths the distance from end to end. Field Shape Elongated to Very Elongated (L/W [GREATER THAN] 3.0)
4. All tests spaced evenly along the long axis of the field, the minimum distance between tests one sixth the length of the field.5. All tests spaced evenly along the diagonal of the field, the minimum distance between tests one sixth the length of the diagonal. Uniform Placement of Percolation Tests--Figures
(a) Square Disposal Fields, L/W = 1.0 - 1.5(b) Rectangular Disposal Fields, L/W = 1.5 - 3.0(c) Elongated Disposal Fields, L/W = 3.0 - 5.0 N.J. Admin. Code Tit. 7, ch. 9A, app C