The grease interceptor has been in use since the Victorian era as a means to reduce the amount of fats, oils and grease, or FOG, that are introduced into sewer systems.
Since that time, the production methods, materials and efficiency of these products have significantly advanced. GIs are now required in most jurisdictions to be installed at any food service establishment. In areas where the authority having jurisdiction has required FOG-producing fixtures to discharge into a GI, the plumbing code states that the interceptor must be certified to one of the following standards: ASME A112.14.3, ASME A112.14.4, CSA B481, PDI G-101 or PDI G-102. These standards prescribe performance criteria and in some cases, design criteria, that the GIs must meet. They also use the same basic test method for determining efficiency and performance. In addition, CSA B481 includes material, hydrostatic and load/structure requirements.
While the above standards contain requirements for hydromechanical GIs, the IAPMO/ANSI Z1001 standard outlines design requirements for typically larger, gravity-type interceptors. Both types of interceptors can be installed below ground, often under high foot-traffic areas such as parking lots and grassy areas outside food-service establishments.
With this installation type, a manhole cover is used as part of the interceptor design to allow access for grease pump-outs and routine maintenance. The familiar manhole covers used in sewer applications, which are typically made from cast iron, weigh between 250 to 300 pounds. This weight prevents mechanical forces from lifting the cover that, in turn, helps protect vehicles and pedestrians. CSA B481 includes requirements for load rating and where that rating must be marked. However, there are no specific requirements for how the cover must be secured. So what happens if the cover is smaller? Or what if it is made from a material lighter than cast iron, such as the covers sometimes used on below-ground installations of hydromechanical and gravity-type GIs?
IAPMO/ANSI Z1001 addresses these concerns with a requirement for securing the cover as well as a note that defines “secure.”
The standard states, “Acceptable measures for securing covers include padlock(s), covers that can be removed only with tools, or covers with a mass of at least 30 kg (66 lbs).” This is a concern because while smaller, lighter covers make it easier to access underground locations for maintenance reasons, they can also expose someone to the risk of personal injury. Unfortunately, the dimensions of the opening are still large enough for a person to fall in and hurt themselves. In fact, there have been a number of deaths, most of them children, associated with falling into underground GIs. One such accident occurred last year in Alabama, prompting the creation of additional regulations at the municipal and state level that closely resemble what is outlined in the IAPMO/ANSI Z1001 standard.
This year, a harmonization process has begun between the ASME and CSA standards for hyrdomechanical GIs. During this process, the requirements of the merging standards are unified and additional requirements may be added. This harmonization provides a perfect opportunity to add specifications for safety, including requirements for securing the covers of GIs intended for installation below ground.
This change would strengthen what is already a robust standard by providing design criteria aimed at keeping the public even safer.
Article courtesy of pme magazine