Frequently Asked Questions Page Two
8. How do I tell how much to pump into the Envirotube?
The first pumpings should be approximately about 4’ or 5’ high. The final pumping to 6’ high. The easiest way to measure this is to place a post on both sides of the tube and run a string across. This can be seen from a distance. Each time the tube is pumped to full height the fabric stretches and becomes weaker. Note: No pumping rate limit
9. How do I determine how much has been dewatered?
When dewatering with Envirotubes, the method of payment needs to be established before the job starts. Remember, haul-away yards will be approximately 1/3 or less of what is removed from the worksite. It is difficult to judge how much sediment is removed by measuring only the Envirotubes. ALWAYS ESTABLISH THE METHOD OF PAYMENT MEASUREMENT BEFORE ACCEPTING A JOB!
10. What sizes are Envirotubes?
Envirotubes are measured by circumference and length. (Always list the circumference first and the length second) The fabric is woven in 15’ width so the common denominator for circumference is 15’ The circumference of the Envirotube will be 15’, 30, 45’, or 60’. Any length to 200’ is common. The larger the circumference, the lower the unit cost of dewatered CY [cubic yards]. The Envirotube lays out half of its circumference in width by whatever custom or standard fabricated length.
There are two CY measurements for the jobsite. One is the in situ CY [CY of sediment before removal]. The other is haul away CY [the dewatered CY of solids in the tube]. The difference is usually 3 to 1. The in situ sediment will usually shrink 3 to 1. For each 100 CY of sediment removed, about 33CY will be left dewatered in the tube. Our hanging bag test will show this ratio. (Please request a Hanging Bag with instructions from IFI). Example: A 45’ circumference Envirotube will hold a maximum of 4 haul away CY per linear foot. A 60’ circumference Envirotube will hold a maximum of 6 haul away CY per linear foot. With a shrink rate of 3 to 1, 1 linear foot of 60’ circumference Envirotube for every 18CY of in situ is necessary. Note: Very organic material will often shrink more than 3 to 1.
11. What size Envirotube should I use?
12. How do I place the Envirotubes?
• The Envirotube must either be placed on level ground and or be restrained to prevent rolling. If the tube is placed on a grade crosswise, the lowest tube must be pleaced and filled first. This must be restrained by a berm or structure for it to lean against. The sewn on handles will not hold it. The next tubes can be placed to lean against the first tube. This will prevent roll. If the Envirotube is placed on a grade lengthwise some capacity will be lost. This will also cause stress on the Envirotube. A 1% grade or more will require special instructions on a 50' long or longer Envirotube.
• The other concern on the Envirotube installation is erosion. There is a lot of water, anything other than a hard surface (blacktop or concrete) will erode. A plastic underlayment will prevent this. The tube dewaters out the top so no porous underlayment is needed.
13. How do I empty the Envirotubes?
Empty the Envirotubes from either end. In order to prevent a mess from weather, do no cut open the Envirotubes full-length. By opening the Envirotube on on end, the bottom Envirotube fabric can be driven on to access the dried material. This will eliminate movement of the fabric.
14. What to do with the fabric from the tube and can it be used again?
There is no practical way to close the tube so it can be used again; therefore, the Envirotube is a one time use. Also, every time the Envirotube is pumped the fabric stretches and weakens; however, it has secondary uses as a geotextile. Landfills and landscapers use the fabric but do not expect any financial compensation.