• What is the life expectancy of a fibreglass Pre-Fab?

Since fibreglass is a relatively new product, we only have history of buried tanks in this service dating back to approximately 1965. Inspection of these earlier tanks has shown no corrosion of any significance. Although sewage service is relatively mild for any fibreglass resin, we know that the resins of today are superior to those back in the 60’s. Based on these facts, we can only assume its useful life expectancy to be in excess of 70 years and probably well past 100 years.

• How do our customers deal with any modifications to existing fibreglass stations?

With the large number of FRP stations in operation, we have been asked to do a variety of alterations over the years. Examples are adding additional height, installing additional inlets, increasing pump sizes, new discharge piping, installing new intermediate platforms, replacing complete tops etc.. Although some alterations require qualified fibreglass laminators, in many instances we are able to provide a package of material and instructions to allow local contractors without fibreglass experience to do the alterations themselves. In every case, we take responsibility for seeing the job is done properly.

• What are the effects of high water tables on an FRP prefab stations?

This is an application where the FRP Prefab has many advantages. All Flygt stations are designed for full hydrostatic head outside the station while empty. Unlike individual stacked rings of concrete with minimal sealing, the entire tank is completely sealed to prevent any soil contamination or infiltration of ground water. A prefab does require however some additional concrete in the form of a bottom slab and possibility a second pour to counter the potential hydraulic uplift at the site.

• Will a concrete station lined with epoxy or PVC perform as well as an FRP Prefab with respect to corrosion?

Concrete will allow liquid to permeate through its structure. In a high water table the external pressure can force the lining away from the concrete resulting in liquid pockets behind the liner and in some cases, complete separation.

• Why do we Recommend fibreglass discharge piping?

Although we have been providing FRP piping inside the vast majority of our stations for over 25 years, many design engineers in the water and sewer industry are simply not familiar and therefore uncomfortable with the product. We remind you that this piping has been used in severe environments such as pulp and paper mills and chemical plants since the 1950’s. Our design is for 200 psi; the warranty is for 5 years; there is corrosion protection both inside and out; the piping is aesthetically pleasing and easy to clean; and the smooth interior has a superior slip coefficient to carbon steel pipe. All nozzles are made of FRP with either a machined or flanged end. The nozzles are laminated to the tank both inside and out and gusseted as required for strength. Unlike some competitors who use incompatible materials in their nozzles, which rely on a mechanical bond to the tank shell (PVC, steel), our construction ensures a completely sealed nozzle penetration. Once an area gains experience with FRP piping, we see its use increase rapidly due to its many advantages.

• What can be done to reduce Confined Space Entries into these Pre-Fabs?

This is an area of growing concern. In response, we have designed new features to address this issue. Either an above ground or side mounted valve chamber locates valves and gauges in a dry compartment where confined space procedures are not required. Available options designed with confined entry in mind include a trash basket on a guide rail system to the lid, sluice gates on inlets with an operator extension, internal spray nozzles, external pump out and bypass lines, inlet nozzle deflectors removable from the top, external valve operators; and level regulator hangers, transducers or stilling wells mounted at surface. These options can make confined entry an infrequent occurrence.

• How do we deal with a requirement for H-20 loading?

When the customer has specified a requirement for H-20 loading, we provide an open top fibreglass station. We can supply or the contractor supplies a concrete top made to fit the open top of the Pre-Fab. There is an extra heavy flange at the top of the station for the concrete top to rest upon. Guide rails and other equipment leading to the top are secured within the fibreglass chamber and are positioned to correspond with appropriate openings in the concrete lid and access hatches.

• How can we assist you at the design stage and in preparation for a quote?

We have available to you preliminary sketches and the design specification for our prefabs in pdf format. If you complete the information required on these forms, we can produce a shop drawing to accompany the bid package. We also have an extensive library of past AutoCad drawings, which can be made available upon request.

• How do I obtain a quotation on a station or further information?

Contact your local ITT Flygt Canada representative:
http://www.ittflygt.ca/