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1-4 Acceptability

1-4.1 General

Besides load type, packaging acceptability is one of the principal standards of mailability. A container must not be packed in a way that might cause or allow its contents to injure Postal Service employees or to damage other mail or mail processing equipment. Fragile items must be packed to withstand mail processing and transportation. Heavy items must be braced and cushioned to prevent damage to other mail.

Items described in 1-4.2 through 1-4.5 often cause problems when improperly packaged. Requests for exceptions to the requirements in this section must be made to a rates and classification service center (RCSC) (see Appendix B for addresses).

1-4.2 Stationery

Stationery items often become loose during mailStationary packages. processing. Problems are caused by unrestrained, concentrated, or shifting contents and by inadequate internal packaging, containers, closures, and reinforcements.

Stationery items that are thicker than 1 inch or heavier than 1 pound may not be mailed in letter-style envelopes. These items must be unitized by tying or banding them or by partitioning tight containers to prevent shifting.

1-4.3 Liquids

1-4.3.1 ContainersLiquid filled containers.

Liquids can damage or destroy other mail and mail processing equipment. Generally, containers of liquid with only friction-top closures (push-down type) are not acceptable. Screw-on caps, soldered tops, clips, or other means are necessary for secure closing.

Glass and other breakable containers holding more than 4 fluid ounces must be cushioned with a material that can readily absorb any leakage. These primary containers must be placed and packed inside sealed, leak-proof containers. If a container holds more than 32 fluid ounces, it is not acceptable for mailing unless cushioned as described above and packed within another sealed, leak-proof container such as a can or plastic bag. The outer mailing container must be strong enough to protect the contents, must be marked "LIQUID," and should display orientation markings (i.e., up arrows) that indicate the upright position of the parcel.

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1-4.3.2 Exceptions

Steel pails and drums with carrying handles and positive closures (such as locking rings or recessed spouts under screw-cap tops) are acceptable for mailing without additional packing. Requests for exceptions to these requirements must be made to the nearest RCSC (see Appendix B for addresses).

1-4.4 AerosolsSpray paint, bugicide and other aerosol containers.

Aerosol containers with inadequate friction-cap closures or other nonpositive means to prevent accidental discharge of contents can injure Postal Service employees or damage other mail and mail processing equipment. These containers must be constructed to prevent accidental discharge of their contents in the mail.

Recessed valves, screw-thread caps, tape closures, or other secure closures can make such containers acceptable.

1-4.5 High-Density LoadsBowling ball and mechanical tools.

High-density loads (such as tools and machine parts) can be dangerous to Postal Service employees and to other mail and mail processing equipment. High-density loads that weigh between 15 and 35 pounds are machinable on Postal Service mail processing equipment if the loads are packaged so that they do not exert more than 60 pounds of pressure per square foot (0.4167 pound per square inch) on the smallest side of the mailing container.

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