Venting

Protect your chemical storage tank system by ensuring your venting is set up properly. Here’s a look at our Do’s and Don’ts when it comes to venting.

Tank venting sticker

1. Do Not Pipe Multiple Vents Into a Common Line

If a common line is used, contact Poly Processing to ensure proper vent size.

Vent Line CorrectVent Line Incorrect

 

2. Do Not Reduce Vent Size or Vent Line

Do Not Reduce Vent Line or Vent Size CorrectDo Not Reduce Vent Size or Vent Line Incorrect

3. Keep 90 Degree Bends to a Minimum – 3 or Less Are Recommended

Minimum 90 Degree Bend CorrectMinimum 90 Degree Bend Incorrect

4. Keep Vent Lines Clear of Restrictions

Vent Line Clear of Restrictions CorrectVent Line Clear of Restrictions Incorrect

Venting charts based on recommendation and criteria from Venting Design for ACFM Technical Paper.

Mechanical Pump Fill Pneumatic Fill
IF ≤ 1,000 gallons IF – Vent length ≤ 3′ IF – Vent length > 3′ and ≤ 30′ IF – Scrubber or fume tight application
✔ Vent size should equal size of largest fill or discharge fitting ✔ Maintain vent screen mesh size ≥ 1/4″ or no screen used ✔ 3 or less 90º elbows with no other restrictions or reduction in pipe size ✔ Vent pipe size throughout scrubber system CANNOT be reduced!
✔ Centerline of dispersion pipe not to be submersed > 6″
IF > 1,000 gallons ✔ Emergency Pressure Relief Cover Required IF > 1,000 gallons ✔ Emergency Pressure Relief Cover Required IF > 1,000 gallons ✔ Perforated dispersion pipe must be same diameter as vent or larger. Sum of perforations ≥ cross-sectional area of pipe
✔ Vent size should exceed the largest fill or discharge fitting by 1″
Tanker Discharge Inlet/Fitting Size Minimum Vent Size Tanker Discharge Inlet/Fitting Size Minimum Vent Size Tanker Discharge Inlet/Fitting Size Minimum Vent Size
2″ 2″ 4″ 2″ 2″ 6″ 2″ 2″ 6″
3″ 2″ 6″ 3″ 2″ 6″ 3″ 2″ 8″
3″ 3″ 6″ 3″ 3″ 8″ 3″ 3″ 10″