The Load Reduction and Arching Effect of Geofoam on Culverts & Pipelines

By: Terry Meier, Geofoam Specialist

It has been stated that an amateur sells products, a professional sells solutions to problems. One of the many problems that Geofoam solves is vertical load reduction on underground structures. The problem of earth pressure on deeply buried utilities has a great practical importance in constructing embankments over utilities.

EPS Geofoam blocks have been used for load reduction on buried utilities since 1988. The 100 to 1 weight ratio difference between conventional fill material and Geofoam brings about a significant load reduction on underground structures such as pipelines and culverts. In addition to its ultra-light weight advantage Geofoam has well defined compressibility characteristics which allow for controlled compression and yielding.

Copyright ACH Foam Technologies' EPS Geofoam

Geofoam also creates a compressive soft zone layer above the utilities.  The soft zone (Geofoam) compresses more than the surrounding fill and thus induces positive arching above the utility. Earth pressure on deeply buried utilities is greatly affected by this arching effect. Arching diverts soil pressure away from the utility thus reducing expected vertical earth pressure.

postitive-arching-effect arching-effect negative-arching-effect

A better understanding of the arching effect of EPS Geofoam on buried utilities has been obtained from field study full scale test measurements. Four instrumental field tests using Geofoam for load reduction on buried utilities were performed over a four year period. The Geofoam was placed above the utilities. Hydraulic pressure cells were placed at various locations above and adjacent to the utility to measure vertical and horizontal earth pressures.


Using Foam-Control® Geofoam was successful in reducing the vertical loads on the buried utilities. The average measured earth pressure above the crown of the utility ranged from 23% to 45% of the overburden pressure depending on the type of backfill which was used. Long term monitoring of the installations indicate no increased pressure on the buried utilities. Once again Foam-Control® EPS Geofoam is indeed a problem solver.

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Key Features to Evaluate When Selecting Roof Insulation

By: Brent Tanimoto, Sales Representative – Architectural Products

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With 2017 upon us and New Year’s resolutions in full swing, it time to consider ACH Foam Technologies’ Foam-Control® Plus+® architectural roof insulation needs?

Let’s take a moment to review a few of the advantages to using Foam-Control® Plus+® in your roofing application:

    • Expanded polystyrene (EPS) is highly customizable and versatile. Unlike other rigid insulations, EPS is available up to 40 inches thick and can be factory cut to nearly any size or shape. Because of this, fewer layers are required to achieve R-Value, resulting in less applied squares and significant labor savings.
  • Available in four different compressive strengths, up to 60 psi, Foam-Control® Plus+® is an extremely durable material and offers the highest R-Value per dollar, with up to 30% savings over tapered ISO systems.
  • Unlike XPS and ISO, EPS does not contain blowing agents, which results in a loss of R-Value over time. This is known as thermal drift and in January 2014, the roofing industry changed LTTR R-Value testing which shows that XPS & ISO can lose their thermal stability over time. This did not affect Foam-Control® Plus+® insulation.
  • Foam-Control® Plus+® is compatible with almost all major single-ply roofing systems and meets or exceeds ASTM C578 requirements.
  • EPS is a closed cell insulation that not only has superior moisture resistance, but has a high drying potential with the ability to quickly release any absorbed moisture.
  • ACH Foam Technologies’ Foam-Control® Plus+® architectural roof insulation is environmentally sustainable. It is 100% recyclable and may contain up to 25% recycled content. Our material contains no dyes, formaldehyde or HCFC’s and can contribute towards LEED® credit requirements.

For more information on roofing products and applications visit ACH Foam Technologies website. On behalf of everyone at ACH Foam Technologies, we wish you a happy and prosperous New Year!

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You Can Trust Geofoam

By: Nick Harvill, Sales Representative

nick-harvillGeofoam is a cellular plastic material that is strong with a very low density, one percent of traditional earth materials. Geofoam has been used in engineering and geotechnical applications worldwide for more than 30 years. Yet many engineers seem to be leery of the load carrying capacity of Geofoam and specify the highest grade to be cautious.

EPS Insulation is specified using ASTM C578. It lists the physical properties of each grade and the insulation value. The compressive strength is listed at 10% deformation. This value is listed for comparison purposes of various insulations and is measured near the failure point. For loading purposes, it has been recommended that 1/3 of this value be used. But for Geofoam use, we have ASTM D6817. It lists the load carrying capacity of each grade of Geofoam at 1% deformation. The compression test is also different from the Insulation compression test to better simulate Geofoam use. This takes the guesswork out of designing for loads.

However, many Engineers do not seem to trust the data. Recently, one engineer specified EPS 46, a material capable of carrying 2680 Lbs./sf, under a 4” retail slab supporting only the store and its occupants. Usually an application like this would require EPS 15 at 520 lbs./sf capacity. EPS 15 is the most commonly specified Geofoam grade; used in stadium and theatre seating, slab on grade fill and other areas where the Geofoam is only needed to provide low load fill. Not only did they specify EPS 46, but they specified 6” steel reinforced knee walls every 5 feet to the existing slab. Under this construction, the Geofoam is not really carrying any load at all and EPS 15 would have been more than sufficient.

Geofoam provides High Strength. It has Predictable Performance with No Settlement. Densities are engineered for applications. If the load approaches the limit of a grade, it is economic to increase to the next grade for safety. Geofoam has Low Water Absorption and is economical, especially when the correct grade is used. Geofoam is:

  • Easily Modified on Jobsite
  • Variety of Sizes & Shapes
  • Termite Resistant
  • Environmentally Friendly

Geofoam has been used in engineering and geotechnical applications worldwide for more than 40 years. In a correctly designed application, it will perform for the life of the project.

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‘Tis the Season for DuraTherm EPS Foam

By: Chris Benson, Packaging Specialist


Recycled insulated shipping container decorative snowmen

December is here….time to start planning time to be with family and friends.

ACH Foam Technologies is entering, one of, if not our busiest month of the year. This reminds me of all the different ways DuraTherm® EPS foam is used in December. From DuraTherm® Insulated Shipping Containers for food shipments (steaks, cakes, and other confectioneries), to DuraTherm® Custom Molded Packaging to help ensure Santa delivers everyone’s gifts in one piece. Duratherm PLUS+™ Validated Seasonal Shipping Solutions ensure medications and life saving drugs arrive to our loved ones that need them. My favorite might be ACH Foam’s DuraTherm® Wine Shippers, whose contents might help many of us during this hectic month!

On behalf of everyone at ACH Foam Technologies, we wish you a Joyous and Happy Holiday season!

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The Rigid Insulation Of Choice For Cold Storage Applications

By: Fernando Dias, Sales Representative


The demand for quality and healthy foods have sparked a recent increase in Cold Storage facilities being built throughout the U.S. People are wanting fresher foods with shorter life cycles. This means logistically having more distribution facilities throughout the market place. These new facilities ensure quality and freshness of their products.

One of the most important building components of a cold storage facility is the rigid insulation. ACH Foam Technologies’ Foam-Control® Plus+® has been the rigid insulation of choice by many designers. Over the last few years designers have come to realize that the benefits and features of Foam-Control® Plus+® out performs all other rigid insulations. One of the biggest benefits is our 50 year R-value warranty, by specifying Foam-Control® Plus+® designers have the peace of mind that the R-value will not decrease over time, ensuring long term performance of their design. Studies also have shown in real world applications that Expanded Polystyrene (EPS) has out-performed Extruded Polystyrene (XPS) in R-value and in moisture resistance for long-term applications.

ACH Foam Technologies’ Foam-Control® Plus+® comes in high compressive strengths of 15, 25, 30, 40, and 60 psi and in many different sizes ranging from ½” to 36” thick and in 2’ x 8’ or 4’ x 8’ sheets. ACH Foam Technologies has eight manufacturing facilities across the U.S. and is likely to be within 500 miles from the jobsite.

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