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LowFlow™ DEVELOPMENT
LowFlow™ Sustainable Protection and Drainage
for Foundation Waterproofing

 

 

  

 

 
 
REDUCE LIABILITY
If you use foundation
waterproofing you are
required to protect it.
 LowFlow™ gives not only protection, but drainage too. The two component geotextile fabric system helped to draw ground water and surface water down the wall into a drainage pipe. Hydrostatic head pressure is also reduced. Less water and less head pressure mean less liability.
 
REDUCE COST
Currently specified drainage systems
often double the waterproofing cost.
 LowFlow's drainage feature comes at no additional cost over that of a protection system alone. LowFlow's drainage rate is not as high as conventional systems, but it exceeds the groundwater feed rate of the soils on many construction sites.
 
REDUCE LANDFILL
LowFlow™ is fabricated from 100% post-industrial recycled synthetic materials.
 Until recently, these materials went to landfills. Now we have found how to reprocess them for this alternate use as a geotextile. An innovative recycled geotextile, which we can make available at a price well below that of virgin materials.
 
The Birth of a New Product...
As an ISO 9001 certified company, Polyguard's new product development process is required to demonstrate a high amount of thoroughness. The LowFlow development story is an interesting one.
   
In late 1996, while searching for improved systems to protect waterproofing membranes, we ran across an unusual recycled geotextile material. This two component fabric had high puncture resistance, which is critical for waterproofing system protection. We tried it as a protection system. It met with enthusiasm, because it was tough and easy to install.

Try puncturing
a sample with a knife.

Feel the resistance.
   
Geotextile experts told us that our new protection system had some drainage capability, so we sent it out to TRI Environmental's laboratory for ASTM flow testing. It did indeed have some flow capacity.
ASTM D 4716 - Flow Rate 0.84 Gallons/Minute/Foot
 
Because of its much lower flow rate compared to conventional "waffle board" foundation drainage systems (which have a flow rate of 15 gal/min/ft.), we named the product (surprise!) "LowFlow™".
  

In order to find out where a product with a low flow rate was usable, we asked the geotechnical engineering consulting firm of Sprague and Sprague; "Which soil types and foundation depths could utilize a product with a lower flow rate?". The answer was that there were many soils and construction projects where LowFlow™ had more than adequate capacity.
  
We converted the engineering results to a table which shows how much water will permeate through varying soil types along a 100 feet long foundation wall. For example, the table shows that a silty clay soil will deliver approximately 6.0 gallons of water each hour to a 100 foot length of 20 foot deep foundation.
 
DRAINAGE MAT SPECIFICATION - BY SOIL TYPE
(Based on required wall drainage (gallons / hour / 100 feet of foundation length)
Using ASTM D4716 Transmissivily and Design Safety factor of 100x
 
For soil types and foundation depths
with flow rates of less than 50 gallons/hour,
LowFlow™ protection and drainage mat may be used
        
Foundation
Depth (ft)
Clay
Silty Clay
Sandy Clay
Silt
Silty Sand
Fine Sand
Well Graded Sand
Uniform Medium Sand
Uniform Course Sand
5
.03
.3
1.8
18
30
120
3000
10
.18
1.8
12
120
180
600
For these soil types
and foundation depths,
consult with a
soils engineer
15
.42
4.2

18
180
420
1800
20
.6
6.0
30
300
600
2400
30
1.2
12.0
60
480
1200
4200
40
1.2
12.0
60
600
1200
5400
50
1.8
18.0
120
1200
1800
7800
60
2.4
24.0
120
1200
2400
For soil types and foundation depths with drainage of 50 to 7800 gallons/hour a combination of LowFlow™ and Flow 15P may be used
 
With a design safety factor of 100 applied to its 0.84 gal/min/ft tested flow rate, LowFlow™ should drain away approximately 50 gallons of water from a 100 foot length of foundation in an hour's time. The framed areas on the table show where LowFlow™ is most suitable. In medium flow conditions, a combination of LowFlow™ and "waffle board" systems such as Polyguard's Flow 15P are more suitable. For extremely permeable sandy conditions, a soils engineer should be consulted.
 
We were curious to know...
 
Now that we had a drainage system suitable for low permeability soils, how much of the country could use the new LowFlow™ product. We asked the Soil Conservation Service (part of the USDA) to prepare a map, based on the national soils data base, showing which parts of the U.S. typically had low permeability soils.
 
 
The map above is, of course, not suitable for project design. Rather the map is an interesting generalization about geographic areas. Within any given area, a wide variety of soil permeability conditions can occur.
And even where it can't keep ahead, it can still help relieve hydrostatic head pressure and reduce the period of maximum ground water exposure.
But the map does show us that there are many construction sites across the U. S. where LowFlow™ can keep ahead of soil seepage.
All of this tells us at Polyguard that we have a new product which meets a need. And the growth in sales and installations of LowFlow™ is confirming our conclusion.
 
The information provided here is based on our best knowledge, but POLYGUARD PRODUCTS, INC. does not
warrant the results to be obtained or intend anything as a recommendation for any use except as described here.
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As of 9/1/2003, Polyguard Products' quality system has been certified to American, Dutch, and German quality systems requirements:
- American Natl. Standards Institute
- Dutch Council for Certification
- Deutscher Akkreditierungs Rat