Transporting Products In Multi-Wall Shipping Sacks

Applicable Tariff Specifications

Shippers are advised to consult the following publications for applicable minimum specifications for paper shipping sacks:

(Uniform Freight Classification) – Rule 40, Section 10 of the Uniform Freight Classification, published by the National Railroad Freight Committee: R.P. Otis, Tariff Publishing Officer, 151 Ellis Street N.E., Suite 200, Atlanta, GA 30335. Telephone 404/659-6266.

(National Motor Freight Classification) – Item 200 of the National Motor Freight Classification, published by the National Motor Freight Traffic Association: Martin E. Foley, 2200 Mill Road, Alexandria, VA 22314. Telephone 703/838-1810.

Hazardous Materials Regulations

Several publications are helpful on the transporting of hazardous materials. For a summary of regulations specific to multi-wall shipping sacks, please refer to “PSSMA Hazardous Material Packaging Guide”. This booklet can be purchased through the Publications section of this website.

Also consult the book “Recommendations on the Transport of Dangerous Goods” published for the United Nations by United Nations Publications: Sales Section, 2 UN Plaza, Room DC2-853, Dept. 1001, New York, NY 10017. Telephone 800/253-9646.

Also consult the Bureau of Explosives’ Tariff on “Hazardous Materials Regulations of the DOT”. Bureau of Explosives Publications: P.O. Box 1020, Sewickley, PA 15143. Telephone 412/741-1096.

Also consult the International Maritime Organization: 4 Albert Embankment, London, SE1 7SR, UK. Telephone 44/020-7735-7611.

Domestic and Export Shipment of Products Purchased by the Federal Government

Consult Federal Specification UU-S-48 “Sacks – Shipping, Paper.” Copies of specifications may be purchased from the Superintendent of Documents, U.S. Government Printing Office.

Specifications for Packing U.S. Department of Agriculture, Dairy Products and Processed Grains

Consult “Announcement CMO-1,” USDA/ASCS, Washington, D.C. 20250


The above specifications are minimum specifications. Considering the climates and distances to which some products are shipped in domestic and foreign commerce as well as typical handling, shipping and storage conditions, constructions that are more durable than the minimum may be required to ensure safe delivery of the product.

Selection and Preparation of Cars

Cars selected for the transportation of shipping sacks must be clean (all dust and dirt must be removed) and have secure roofs, smooth floors and walls and tight-fitting doors. They must be free from protruding nails and other hazards.

Sacks should not be loaded in wet cars or in cars showing oil, acid or similar stains or in cars with contaminating odors. Food or feed sacks should never be loaded in cars in which there is evidence of insect infestation.

Freight Cars

Floors must be swept clean of all pebbles, grains, sand and grit. In addition, these materials must be removed from under side boards and in spaces between side boards.

Nails and Staples

The nails and bolts used in car construction must be tight. Protruding staples must be eliminated to assure damage-free transit.

Car Lining

When car floors and walls are not smooth and clean, they should be covered with at least one thickness of 50 pound basis weight kraft paper or two thicknesses of 30-pound basis weight kraft paper. A single thickness of adequate paperboard, corrugated or other liner materials specifically made for the purpose may also be used.

Floors must be swept clean of all pebbles, grains, sand and grit. In addition, these materials must be removed from under side boards and in spaces between side boards.

Car Lining

When car floors and walls are not smooth and clean, they should be covered with at least one thickness of 50 pound basis weight kraft paper or two thicknesses of 30-pound basis weight kraft paper. A single thickness of adequate paperboard, corrugated or other liner materials specifically made for the purpose may also be used.

Lining materials should not be applied over nails, raised or loose staples or anchor plates. If staples are used they must be firmly secured and not protrude through the paper surface. Lining paper can be applied with adhesive brushed on walls or with short strips of adhesive tape. Paper should be high enough on the walls to provide adequate protection for the layers of sacks to be loaded. To prevent damage from moisture or dirt to the top of the load, lining paper on the sides and end walls should be of sufficient dimension to permit its being folded over the top of the load.

Corrugated paper is often helpful for covering uneven floors and side walls.

Where car sidewalls are rough and there is a possibility of the lining paper wearing through and exposing the walls, pyramid loading away from the walls is essential.

Loading Full Cars

When loaded in cars, filled paper shipping sacks should always be stacked flat. The most satisfactory loading patterns are interlocking methods similar to a “brick wall” construction. A number of variations of brick wall patterns are possible, depending on the size of the sacks and dimensions of the car. Tight loading is essential so that pressure between sacks and car walls reduces the tendency for movement. Dunnage bags or other materials can be used effectively to brace the load to reduce movement during transit.

The weight of lading must be approximately the same on each side of the car, and freight used in closed cars must be loaded to prevent contact with the car doors during transit.

Each shipper should determine a loading pattern to assure a tight interlocked mode. This will minimize cargo shift in transit and keep car doors free of sacks.

Necessary Precautions

All loading equipment used to handle paper shipping sacks should be inspected regularly. This includes conveyors, chutes, and hand trucks; each item must be free of sharp or protruding hardware or splinters.

Paper shipping sacks which are excessively dry or moist should not be loaded in cars, since they may be more easily torn by handling. Storage facilities should be located and equipped to maintain the desired 6-8 percent moisture content. This is best accomplished by storing sacks at a temperature of 70 degrees F. and a 50-60 percent humidity level.

Special care should be taken with products packed at high temperatures as sacks tend to become dehydrated and brittle unless exposed to proper storage conditions before shipping.

Some materials are insulators by nature and when shipped in a railroad car could arrive at their destination almost as hot as when they were packed. To avoid possible damage, filled sacks should be cooled before shipping.

If materials must be packed at high temperatures, paper shipping sacks specially constructed to withstand high temperatures should be used. In addition, the moisture content of the unfilled sacks for packing such products should be kept at the highest level possible.

Loading in Mixed Cars

Substantial labor savings can often be achieved by loading sacks in cars in stable, palletized units, interlocked or assembled to form a tight load using one of the methods outlined earlier. If this is not possible, the units should be adequately protected from forward or crosswise movement during shipping with adequate dunnage at all points required.

Loading Pallets

When paper shipping sacks are loaded as mixed shipments with other containers or with other types or sizes of sacks, the different containers should be loaded as segregated units. The sacks should be secured against movement by the use of the same methods prescribed for full car loading.

Sheets of fiberboard or inflatable dunnage may be used to separate units of different types of sacks and furnish smooth loading surfaces for contact with the containers.

Doorway Protection

Car doorways must be protected against the possibility of sacks shifting or coming in contact with doors. One method uses a sheet of heavy fiberboard of sufficient length to cover steel straps or wood members and extends beyond door posts. Straps should be applied tightly across the doorway opening. Prefabricated steel strap reinforced retaining strips can also be applied tightly across doorway openings.

Car Doorway Loading

Sacks should be loaded in car doorways in such a manner that a part of the load acts as a keystone between the load in the two ends of the car. The loading method used should lock the entire load together to minimize shifting in transit. The brick wall configuration in the doorway area is preferable and may be used in conjunction with any type of load. Adequate setback should be allowed to prevent damage from shifting.


Most damage to filled shipping sacks in carload shipments occurs in car doorways. Extreme care should be exercised in opening doors. Car doors should never be forced open but should be opened slowly and only far enough to determine whether sacks have jammed against the door during transit. If sacks are jammed against the door, the opposite door should be used.

In unloading cars, special attention should be paid to sacks in bottom tiers on the floor. Sacks in bottom tiers should be turned over before lifting to determine if they have been punctured by nails or some other hazard.

Motor Trucks

Preparation of Trucks

When loading paper shipping sacks, the some general care taken in the preparation of freight cars must be exercised in the preparation of motor trucks.

Trucks must be free of protruding nails or other sharp projections. Floors must be clean of all pebbles, grains, sand and grit. All pieces of rough or sharp material which could damage the load should be eliminated. Sacks should not be stacked directly on wet platforms or in trucks showing oil, acid or similar stains or in trucks with contaminating odors.

Loading and Protection of Load in Transit

Filled paper shipping sacks should always be loaded flat, in solid interlocked loads. Before loading sacks, it is recommended that trucks be lined with fiberboard or commercially available linerboard. Skid straps should be securely fastened. Tarpaulins should be used to cover loads in wet weather. Sharp or irregular merchandise should never be piled on filled sacks.

Unloading Motor Trucks

Unless filled paper shipping sacks are shipped on palletized units, they should be unloaded from the truck manually. Sacks should be lifted with hands underneath, supporting both ends. Hooks should never be used. Sacks should be carried at waist height, flat on the shoulder or by hand truck. To avoid damage, sacks should never be held by the ends, dragged on the floor or pulled over other merchandise.

Ocean Vessels

Commodities destined for export shipment by ocean vessel normally require heavier packaging than is required for domestic shipment. However, with the development of unitized containers, domestic packaging can sometimes be used for export shipping.

As a general rule, packaged commodities for ocean shipment must withstand five times more handling than commodities packed for domestic use. Exported products must be protected from the natural humidity of a ship’s hold and from the effects of climate extremes. Many ports and steamships use obsolete equipment such as rope slings which tend to damage sacked and other fragile cargo. Furthermore, many countries have crude cargo handling facilities.

Export Packaging

Multi-wall sacks can be designed to withstand the hazards and additional handling of ocean shipment. Such constructions can also successfully meet the severe export conditions described above, as well as prolonged open storage.

Export shipment usually requires stronger, more positive closures. Top closures should be as strong and sift-resistant as bottom closures and should not allow excessive tape or thread lengths at corners since handlers sometimes open sacks accidentally by pulling a long tape or thread.

Sewn closures should be stitched three or four to the inch and should be sewn parallel to the top of the sack. Closer stitching may weaken the top. Stitches should be cushioned with cotton or paper filler cord. Sewn closures should be taped before or after stitching.

Equipment for Loading

Filled paper shipping sacks should be stowed aboard and discharged from ships by the use of canvas slings of adequate length, platforms with spreader bars or palletized loads. All gear used should be able to prevent ropes or cables from damaging sacked cargo. No hooks or dragging devices should be used.

Wooden platform slings should not be raised from nor lowered onto unprotected stacks of paper sacks. Cargo with sharp edges and corners should be stored and unloaded separately. Sacks should be stowed at least six inches away from beams and the skin of the ship. Beams and angles should be covered with liner paper and a light tarpaulin should be used to cover loads.

Cargo in filled shipping sacks should be stowed away from steam pipes or other heating units. Sacks should be kept dry with good circulation of air throughout and stowed away from oil, acid or other liquid cargo.

Salvaging Paper Shipping Sacks

Sacks which can be resold or reused should be trimmed below the sewing line. By neatly tucking in the gussets, they can be stacked flat in orderly bales for resale.

The symbol “ANK” printed on sacks signifies that the sack is made of “all natural kraft” and frequently may be repulped. The “recyclable” symbol on a shipping sack indicates materials used in the sack are normally recyclable. Assuming the necessary recycling infrastructure exists, actual recyclability of a shipping sack depends on a number of factors. Sacks constructed with plastic liners, wet strength paper or other types of non-water-soluble papers (including tapes and sleeves) may not be salvageable for repulping. The end use of a paper shipping sack may also affect suitability for recycling.

Taking Samples Of Materials

Often, samples of a shipped product need to be obtained. If the sack has a valve, a sampling tube may be inserted through the valve. When there is no valve, a few stitches should be cut from the sack closure and the sampling tube inserted through the opening. The opening is then closed with staples (for products other than foods or feeds).

When sampling food or feed products in sacks, an opening made by a sampling tube may be closed easily by the use of pressure-sensitive tape. Where provided, state regulations for sampling procedures should be followed.