SECTION 1807.4.2

FOUNDATION DRAIN

A drain shall be placed around the perimeter of a foundation that consists of gravel or crushed stone containing not more than 10 percent that passes through a No. 4 (4.75 mm) sieve. The drain shall extend a minimum of 12 inches beyond the outside edge of the footing.

The thickness shall be such that the bottom of the drain is not higher than the bottom of the base under the floor, and that the top of the drain is not less than 6 inches above the top of the footing.

The top of the drain shall be covered with an approved filter membrane material. Where a drain tile or perforated pipe is used the invert of the pipe or tile shall be placed higher than the floor elevation. The pipe or tile shall be placed on not less than 2 inches of gravel or crushed stone complying with Section 1807.4.1, and shall be covered with not less than 6 inches of the same material.

CODE INTERPRETATION

This section provides the requirements for foundation drain placement. The section is precise in the requirements and provides a basis for design:

• Apply a drain around the perimeter of the foundation that consists of gravel or crushed stone. The gravel or crushed stone shall be a minimum of 4.75 mm or larger.
• The drain shall extend a minimum of 12 inches beyond the outside edge of the footing.
• The thickness shall be such that the bottom of the drain is not higher than the bottom of the base under the floor, and that the top of the drain is not less than 6 inches above the top of the footing.
• Cover the top of the drain with an approved filter material.
• If a drain tile or perforated pipe is used the invert of the pipe or tile shall be placed higher than the floor elevation.
• The pipe or tile shall be placed on a minimum of 2 inches of gravel or crushed stone. The gravel or crushed stone shall be a minimum of 4.75 mm or larger.
• The completed pipe or tile shall be covered with a minimum of 6 inches of gravel or crushed stone. The gravel or crushed stone shall be a minimum of 4.75 mm or larger.

SECTION 1504.7

IMPACT RESISTANCE

Roof coverings installed on low-slope roofs (roof slope <2:12) in accordance with Section 1507 shall resist impact damage based on the results of tests conducted in accordance with ASTM D 3746, ASTM D 4272, CGSB 37-GP-52M or the “Resistance to Foot Traffic Test” in Section 5.5 of FM 4470.

CODE INTERPRETATION

The code implies that all roof covering materials installed on low-slope roof systems shall be tested to determine impact resistance. The impact resistance tests shall be completed in accordance with ASTM D 3746 and/or ASTM D 4272.

ASTM D 3746 is titled “Standard Test Method for Impact Resistance of Bituminous Roofing Systems.” This test is completed by placing a steel cylinder (2 inches wide and 6 inches in length) in a vertical guide tube (4 feet long with 2 3/8-inch diameter). The guide tube is placed a minimum of 53 inches above the test surface. The missile is released to fall and strike the test specimen. A total of four tests — one in each quadrant — are required for each test specimen. At the conclusion of the tests the impact areas are examined for damage. The specimen is rated for impact damage per component. The rating system is as follows:

0 = no damage

2 = dents, indentations only

4 = any cracks or splits

The ratings are applied to each component (plies) in each quadrant, added up and then divided by four times the number of plies to obtain the average for the membrane.

ASTM D 4272, “Standard Test Method for Total Energy Impact of Plastic Films By Dart Drop,” uses the same premise; however, a dart is used as the missile to test pinhole impact.