During our installer workshops, we are frequently asked questions about proper materials for various applications. They include questions on quality of materials, proper installation of materials, potential storage of materials, and advantages and disadvantages of the materials. Before addressing some of the specific material questions, here are some considerations for acquiring and storing proper materials.

It is the installer’s responsibility to use materials specified in the design. An installer who is also the designer is responsible for selecting the proper materials for each application. When a specified material cannot be obtained or the installer feels there is an equivalent material available, the change requires consulting with the designer to make sure it is equivalent and will do the same job. It is also the installer’s responsibility to store and handle the specified materials to ensure they can be used as the designer intended.

Storage can occur in two locations: the installer yard or shop and at the site of installation. Having storage available at the shop allows for ordering certain materials, such as pipe and distribution media (chambers, rock, sand), in bulk. This gives the installer an advantage when bidding the system price. However, improper storage can result in the materials being unsuitable for use, so the installer needs to prepare suitable areas for storage.

It is important that materials are maintained to meet their original specifications. This means distribution rock or treatment sand are not contaminated with native soil. It’s best if the materials are stored on a concrete slab and under cover. If these materials are stored in contact with soil — either at the shop or at the site of installation — some loss of materials (as much as 5% to 10%) can be expected because the sand or rock in contact with the soil cannot be used in the system. This needs to be factored into price of materials. If a storage area is not provided to reduce these losses, it would be best to not try and store the materials.

AT THE JOB SITE

The best way to avoid potential problems at the job site is to not store the material, but to use it on the day of installation. This is not always possible, particularly when installing aboveground systems such as mounds or at-grades. For these systems, it is important to move the clean sand and rock into place from multiple directions. This means there will be some material in contact with soil and losses will occur in the process. Furthermore, the contaminated material needs to be removed from the site and disposed.

One good idea to minimize loss is to prepare a clean, undisturbed area to store the material and keep materials separate once they are delivered. Plan for the placement of the materials in locations where they are readily available for use during the different stages of installation. Having them separated and kept where they do not interrupt work areas or traffic patterns is important. And plan ahead for delivery. Don’t wait until the trucks are there to deliver the materials to prepare an area or figure out “the plan.”

Keep piles of distribution rock separate from the piles of final cover material. Maintain working space between the piles to assure the rock is kept clean and free from silt or clay-size particles that can wash through the rock after installation and seal the bottom of the trench. If rain is expected, it’s best if the piles are covered with plastic to protect them.

STORING PIPE

Proper storage is just as important for other system materials, such as PVC piping, chambers and dropboxes or distribution boxes. Care should be taken when handling materials to avoid contact with sharp objects that can cause cracking or breakage. They should not be dragged across the ground or stored where they can be in contact with soil, which can affect their suitability by reducing strength or forming a crust of fine particles that can impact system performance.

If PVC materials need to be stored for any length of time, they should be kept out of direct sunlight. Sunlight and excessive heat can affect the strength of pipe, chambers and other system components.

A couple of additional comments about storing pipe specifically: It is best to store pipe indoors or at least under cover. When stacking pipes, the thickest-wall pipe should be on the bottom. When pipes are stored on a rack, it is important to support them the entire length. Bowing can occur, which makes those sections of pipe unusable for many applications. If a section of pipe is damaged, it should not be used, rather cut out and discarded.

Other materials to be used in media filters or advanced treatment systems should be segregated and stored according to the manufacturer’s directions. This includes materials such as peat, textile filters, Styrofoam peanuts and plastic media. Media of any type should be protected from soil contamination.

In future columns, we will take a closer look at the specifications for some of the materials, how to determine if the product you are purchasing meets the requirements and why these specifications are important.