IPGC Applications, Benefits, & Comparisons

IPGC Applications

The IPGC drainage pipe is useful for multiple applications and will function efficiently as any of the drainage device(s) below.

Capturing Runoff with the IPGC

The IPGC can be installed to capture runoff from roadways, parking areas, driveways, yards, and virtually any other landscaped or natural area. The two images below indicate the most typical ways to capture runoff in sumps and on slopes. Additional images are used to demonstrate where the IPGC can be installed and provide insight into how it can be used for intercepting, capturing, and routing drainage on commercial sites and residential lots. Just use your mouse wheel to zoom in on them.

IPGC Product Benefits

Performance

The IPGC Trench Drain

The IPGC drainage pipe is an effective, cost-efficient, and easy-to-install trench drain that will readily capture a substantial volume of drainage runoff right at the ground surface. The concentrated and abundant open slit area on the IPGC surface?allows for this optimization. The IPGC Trench Drain?is able to?convey the captured runoff just beneath the surface until it becomes necessary to install deeper lines. At that point, the IPGC can easily be connected to standard PVC pipe with the appropriate standard PVC fittings.

Please Note:
The IPGC Trench Drain is not and should not be confused with a typical French Drain that houses a standard perforated PVC pipe.

The following list describes several benefits of the IPGC Trench Drain not provided by the French Drain:

• The IPGC trench drain will capture drainage runoff right at or just below the ground surface, whereas standard perforated pipes in French Drains typically begin to capture and convey runoff at least 6-12 inches below the ground. The concentrated and abundant open slits on the surface of the IPGC drainage pipe practically eliminate ponding at the surface. With French Drains, a significant portion of the trapped runoff is never conveyed by the perforated pipe, and must filter through the gravel to the discharge location.
  
  
• The IPGC Trench Drain is much simpler to install than a French Drain. This is due to the fact, as mentioned above, that the IPGC open slits are ideally located right at or just below the ground surface. French Drains typically require at least 6-12 inches of gravel covering the entire perforated pipe.
  
  
• Essentially, the required trenching to install The IPGC drainage pipe only needs to be deep enough to enclose the pipe up to the open slit bottoms. It may be preferred in some cases to install a thin 2" layer of at least 5/8" diameter gravel to cover the exposed IPGC open slits. The gravel installed with a French Drain must also be sized appropriately to not fill up the perforations.
  
  
• Essentially, the flow capacity of the conveying pipe is the limiting factor for conveyance. For all standard IPGC pipe lengths, The IPGC has been designed to allow the open slit area to be far greater than the cross sectional area of the pipe itself. Therefore, the IPGC open slits will never inhibit pipe conveyance. With a standard perforated pipe, it takes an unspecified length (depending on the pipe diameter), to provide this benefit.
  
  
• Overall IPGC Trench Drain installation costs will be less than for French Drains due to the fact that no gravel is needed for trench backfill or for trapping runoff beneath the ground.
  
  
• French Drains require cleanout installations if any maintenance is to be simplified, and the cleanouts must be in sight. The IPGC drainage pipe is easily maintained since it is easily accessed and replaced just at or below the surface.
  
  
• Another benefit of the IPGC trench drain is that it can be installed to strategically position the open slits (via rotation), if it is warranted by the situation. A French Drain does not provide an option such as this.

Other Benefits of the IPGC Trench Drain include:

• The costs and efforts required to install the IPGC are much less than for typical grate inlets, landscape drains, catch basins, & storm drains.
  
  
• Filter fabric wrapping is not required for the IPGC if a 2" gravel layer is applied or if the surrounding area is established with suitable vegetation.
  
  
• Installing The IPGC drainage pipe is an additional way (in addition to capturing rooftop runoff) to supplement the water supply for a rainwater harvesting system.

The IPGC French Drain

The IPGC French drain is simply the inverted IPGC Trench Drain with the addition of a bottom gravel layer.  With the open slits facing downward, resting on top of the bottom gravel layer, the IPGC drainage pipe is able to allow substantially more stormwater into the pipe than will a standard perforated pipe. This is because of the abundant open area provided by the surface slits.  With an identical amount of contributing flow, the ponded depth above The IPGC drainage pipe will be less than that which occurs for the standard perforated pipe.  This fact can be verified with the orifice equation.

The IPGC Storm Drain

The IPGC storm drain is simply the drainage pipe itself, however, the IPGC is able to convey stormwater more effectively than a standard perforated pipe with the slits facing upward. This is because the bottom portion of the pipe remains in tact from the flowline up to the bottom of the slits.  If the IPGC is installed with the slits facing downward, as a French Drain, flow is minimally affected by small pockets between the top of the gravel layer and the inside wall of the pipe. These small pockets will hold water until final infiltration into the gravel occurs.  

The IPGC Grate Inlet & Catch Basin

The surface of the IPGC performs as a grate inlet in a sump or on-grade. The actual pipe itself will serve as a catch basin and conveyance device. When the open slits can be exposed at the surface, the open flow area is maximized.

The IPGC Interceptor &  Diversion Device

The IPGC can function as both a drainage interceptor and diversion device since it will simultaneously function as a grate inlet, catch basin, and storm drain.  Along the perimeter of a residential lot or commercial site, the IPGC can be installed to capture flows leaving or entering the property.  Once the contributing flow is captured, the IPGC can be connected to additional PVC pipe as needed in order to discharge at the desired location.

The IPGC Filtration Drain

When wrapped with filter fabric and covered with porous gravel, the IPGC is an excellent filtration drain with the following additional benefit: The additional open flow area provided by the IPGC requires a lower head (or water depth) than a standard PVC perforated pipe to convey the same flow rate. This means that the ponded depth will be lower for any given flow rate at the point of capture.

Detention Pond Outlet Drains

The IPGC is a less costly and equally effective alternative to installing typical pond outlet structures. Additionally, the required open area (for an orifice) can be provided within a tolerance area of one slit. The open width for an individual slit on all available pipe sizes is 0.25-inches. The individual open slit lengths remain constant for a given pipe size, but as the pipe size increases so will the individual open slit length.

Water Quality Pond Riser Pipes

For this application, the IPGC is merely an alternative to perforated pipe, as neither seems to have a distinct advantage or disadvantage. This is because the typical release rate from a filtration pond is small in comparison to incoming flows.

Rainwater Harvesting

The IPGC makes it relatively simple to capture surface water runoff for use in a rainwater harvesting system. The following paragraphs describe rainwater harvesting in a non-technical fashion for those interested in learning about the excellent benefits of rainwater harvesting.

Firstly, rainwater harvesting is an effective means for filtering out pollutants such as suspended particulate matter and associated constituents such as bacteria, nutrients, and metals that originate on impervious surfaces such as rooftops, asphaltic concrete, and even man-made landscaped areas.

Although most rainwater harvesting systems treat runoff that is captured from rooftops with gutters and collection pipe, it is becoming more common to capture, treat, and use runoff from impervious surface areas on a developed property. Once the runoff is captured, it is routed to a storage tank where sedimentation occurs. Storage tanks can be located above or below the ground, but this usually depends on the physical constraints and how the rainwater is to be captured and used. A pump is required for below ground storage tanks when the treated water must be lifted to an elevation where it can resume gravity flow or is dispersed. The storage tank will remain idle for a certain period of time, depending on the pump settings. Once released from the tank, the treated runoff can be used for natural infiltration, landscape irrigation, plant and lawn watering, secondary water supplies for green buildings, and reclaimed for cooling water.

The IPGC can be used for more than just capturing runoff for a rainwater harvesting sytem. It can also be used for disbursing the treated runoff in order to provide natural infiltration of an area, gravity fed irrigation, and pump-fed irrigation. The image below shows two possible rainwater harvesting systems: each has a discharge system comprised of standard and IPGC Schedule 40 PVC piping. To look at a larger image, just use your mouse wheel to zoom in on it.

Please note that these images are schematic representations and should not be used as construction details. We highly recommend that all interested parties consult with a licensed rainwater harvesting professional before installing a rainwater harvesting system at your home or business. A list of nearly 40 rainwater harvesting professionals is available from the Texas Rainwater Catchment Association Website.

The IPGC as an Erosion Control Device

When a section of IPGC is used in a sump location and is either covered with gravel or wrapped with filter fabric, very little sediment can enter the pipe. When used in this fashion, the IPGC can significantly help to minimize sediment transport in addition to removing potential pollutants from the runoff entering downstream waterways. After an unspecified period of time, especially in areas with little or no vegetation in the area contributing runoff to the sump, sediment will inevitably accumulate in the vicinity of an IPGC section. When this occurs, the displaced sediment should be removed in order to restore full functionality of the IPGC as a filtration and drainage device.

If sections of the IPGC are installed parallel to grade (or perpendicular to the direction of flow) and are placed intermittently to intercept surface water runoff, the diplacement of sediment caused by wash out can be minimized because of the flow reduction on the ground surface. If used in combination with silt fencing, the IPGC can help reduce the flow rate through the silt fence. This is desirable in situations where construction has produced an increase in runoff and therefore an increase in sediment displacement.

IPGC Comparisons

• The IPGC clearly provides more open surface area to capture surface runoff:
  
  
• The abundant open area provided by the IPGC allows for more runoff water to enter the pipe which results in a lower ponded depth of water during storm events.
  
  
• Therefore, the IPGC will clearly out perform PVC tees with grate caps.

The IPGC drainage pipe will perform as a grate inlet, catch basin, and storm drain all at the same time. If the open flow area provided on a pipe surface exceeds the cross sectional area of the pipe itself, which occurs with relatively short sections of IPGC, the pipe size will dictate the amount of flow that can be conveyed. As seen in the above photo, the IPGC provides substantially more open flow area on the pipe surface than the standard perforated PVC pipe. The following text discusses several of the inadequacies associated with perforated pipe that the IPGC will effectively accomodate.

The IPGC open slits allow for an unsubmerged flow state if installed fully or partially above the ground surface at the capture point. Each IPGC open slit will perform as a one-sided weir (on-grade) or a two sided weir (in a sump) until the contributing flow is large enough to submerge the entire pipe. The point at which the IPGC open slits become submerged is dictated by several factors inlcuding the pipe size, pipe slope, and the contributing flow rate. The section length of the IPGC is another important factor as larger spans contain more open slits (or open slit area).

• If used as a sump inlet, the standard perforated PVC pipe would become submerged at a lower flowrate than the IPGC since:
  
  
  • The standard perforated pipe was never intended to capture runoff at the ground surface and is therefore installed beneath the surface.
    
    
  • The runoff must first infiltrate the bedding material before it could be captured and conveyed by a buried perforated pipe. Once the bedding material begins to saturate, the perforated pipes will begin to convey. However, if the open slits on the IPGC can be at least partially exposed, conveyance will begin immediately.
    
    
  • The standard perforated PVC pipe would provide less open area at the ground surface than the IPGC and would therefore require additional head to convey the same flow with an equal length of pipe. In order to convey the same flow as the IPGC, with the same required head, a longer section of standard perforated PVC pipe would be required.

• A fully perforated PVC pipe could possibly provide a larger amount of open area at the surface, but the structural integrity would be questionable.

• If used as an on-grade catchment device, a perforated pipe simply cannot compete with the IPGC because:
  
  
  • As the ground surface steepens toward a catchment pipe, the surrounding surface and bedding material absorbs less of the contributing flow. Since perforated pipes are typically always buried, they would not perform well at all as on-grade catchments. Even if a portion of the perforated surface could be exposed, the raised and lengthy open slits of the IPGC will still capture more runoff. The IPGC can be installed to accomodate on-grade surfaces since the open slits can be partially or fully exposed at the surface.
  
  
• Even in situations where the IPGC must be buried, it will still out perform the standard perforated PVC pipe because of the concentrated slit pattern and substantially more abundant open area. When the open slits are facing upward, the IPGC will perform most effectively as a conveyance device. If the open slits are oriented downward or 90 degrees to either side, the IPGC would perform similar to a perforated drainage pipe. However, the IPGC would require less head (or water depth) than the standard perforated pipe to convey the same amount of flow. A fully perforated PVC pipe is also a very good option in fully submerged conditions, but it is not readily available in local hardware stores. In most cases, fully perforated PVC pipe has to be ordered from a manufacturer.