scope:

These standards cover the sanitary aspects of equipment used in systems solely for the pneumatic conveying of dry milk, dry milk products, or other dry comestibles utilizing air flow which is caused by either a pressure or vacuum differential. These standards are not intended to cover pneumatic conveying equipment or systems that are an integral part of a spray drying or instantizing system unless specifically referenced for that purpose in the applicable 3-A Sanitary Standard or 3-A Accepted Practice. The equipment begins at the point at which product enters the conveyor and ends at the point(s) where product is discharged from the conveyor. With respect to air, the equipment begins at the point where conveying air leaves the final filter and ends at the entrance of the air/product separator equipment. These standards also include any required product accumulation, conditioning and metering equipment which are located before product introduction into the conveying air pipeline and which are provided by the equipment manufacturer.

These standards do not cover the use of:

1. Air slide type conveyors which convey product using air flow through a permeable membrane type media or perforated plate.

2. Wand type pneumatic conveying equipment from open containers or bags where ambient air can be introduced to convey product.

3. Product storage bins, hoppers, silos that are part of the air/product separation equipment.

4. Bag collectors, when used as air/product separators, which are covered by 3-A Sanitary Standards for Bag Collectors, No. 40-.

In order to conform to these 3-A Sanitary Standards, pneumatic dry milk conveyors shall conform to the following design, material and fabrication criteria.¹

¹ Use current revisions or editions of all referenced documents cited herein.