Vents and Scrubbers

Venting Requirements for Poly Tanks

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!
	✔ Maintain vent screen mesh size ≥ 1/4″ or no screen used						✔ 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	Min Vent Size	Tanker Discharge	Inlet/ Fitting Size	Min Vent Size	Tanker Discharge	Inlet/ Fitting Size	Min 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″

Click to see guidelines for vent placement.

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

U-Vent

Standard venting for outdoor tanks or for storing chemicals that create fumes. In PVC, in sizes 2 to 6 inches.

Drawings

Proper Venting: Poly Processing Has You Covered

Mushroom Vent

For day tanks, an economical alternative to traditional U-vents or fittings. Made of polypropylene, in sizes 1 to 3 inches.

Drawing

2″ mushroom vent

Proper Venting: Poly Processing Has You Covered

8″ Mushroom Vent Assembly

Until now, space-consuming (and expensive) large vents or multiple vents were necessary to meet venting requirements in order to maintain the warranty. Our solution is an 8” mushroom vent, which is available as a complete assembly in a standalone version. This mushroom vent has been used by Poly Processing Company for several years as part of the F.S. 2650 manway cover. The vent now comes with a flange molded into it so that it can be installed on the dome of the tank to give you greater venting capacity. This is a more cost-effective alternative to many other venting systems.

Like the F.S. 2650, the mushroom vent comes with an HDPE screen to prevent birds from nesting and debris from plugging the vent.

Download a drawing

Proper Venting: Poly Processing Has You Covered

PolyScrub™

We have the ability to produce scrubbers based on our client’s need. Our standard scrubber PolyScrub is comprised of a submerged plenum, which allows fumes to bubble through a water bath.

Literature

For specific questions about vents and scrubbers, please contact a Poly Processing chemical storage tank expert.

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