strength of the tube ends must be equal to the tube sidewall strength, except when the contents are lightweight rolled items. Crimped, masking, or cellophane taped end closures are not acceptable for other than lightweight, rolled items. Tape must completely encircle the seams on friction slide closures of mailing tubes. (6) Cans and drums. Cans and drums are acceptable with positive closures. Generally, friction closures by themselves are not acceptable. Protruding devices, such as locking rings, shall be shielded by padding to prevent injury to Postal employees, equipment or other mail. (c) Cushioning. (1) Cushioning absorbs and distributes forces caused by shock and vibration. Examples of cushioning materials are foamed plastics, rubberized hair, corrugated fiberboard, and loose fill material, such as polystyrene, excelsior and shredded newspapers. Illustrations 4, 5 and 6 show ways of using cushioning material for packaging odd shaped items, picture frames, fragile ceramic articles and electronic equipment. (2) Loose fill cushioning must overfill the container prior to closure to hold the item and prevent its movement to an outside surface of the container or to ILLUSTRATION 4 PACK CUSHIONING MATERIAL IN BOTTOM OF CARTON-WRAP EACH ITEM SEPARATELY. 2 PACK WRAPPED berboard pads and less dense, loose fill material are most effective in force distribution. Shock and pressure forces must be dissipated over as much of the surface of the item as possible. (3) When several items are within a package they must be protected from each other as well as from external forces. Concentrated heavy items must not be packaged with fragile items unless extreme care is exercised to separate the items from each other. Heavy items must be adequately blocked and braced. (d) Closure and reinforcement—(1) General. Closure and reinforcement of packages are primary considerations in the preparation and acceptability of any parcel. The principal methods of closure and reinforcement employ gummed and pressure sensitive tapes, adhesives, strapping, twine and cord; staples for boxes and bags; and various friction closures, screw caps and locking devices for cans and similar containers. (2) Tape. (i) Tape is used for closure, sealing and reinforcement of containers. Cellophane and masking tape shall not be used for closure or reinforcement of packages, but may be used to augment adhesive closures on envelopes or to cover staples on bags. Pressure sensitive, filament reinforced tape is recommended. (ii) Gummed paper tape must be at least 60 pounds basis weight kraft. This tape is widely used for closure and sealing, but is not adequate for reinforcement. Reinforced kraft paper tape is considerably more durable than plain kraft tape, and takes less time and tape for an equal closure. The adhesives on gummed tapes must be adequately dissolved prior to application, by the use of warm water with a wetting agent, and must be firmly applied with the tape extending at least three inches over the adjoining side of the box. Improper application results when the gummed adhesive is not activated or when the water is absorbed by the fibrous container. The tape must be kept from freezing for at least an hour. Care should be taken when extremely cold temperatures are anticipated. Even properly applied gummed tapes tend to crack under these conditions. (iii) Pressure sensitive tapes come with various paper, cloth or plastic backings, both plain and reinforced, and may be readily applied at any temperature above freezing. Application, especially in below freezing temperature, requires that the tape be rubbed down well to assure adhesion. Pressure sensitive tape should be used on the container in the same way as gummed tapes. (iv) Illustration 7 shows proper and improper methods of applying reinforced and gummed paper tapes and reinforced pressure sensitive tapes. Tapes can also be used to close other types of packages not illustrated, including those of irregular shapes and soft wrapped items. Packages properly closed with reinforced tape are substantially stronger than are parcels closed with nonreinforced paper tape. (3) Adhesive. Adhesive is a general term covering cement, glue, mucilage, paste, thermoplastic adhesive, etc. An adhesive must cover at least 50% of the box flaps and should be applied not more than 1/4 inch from the ends of the box flaps. (4) Strapping, twine, and cord. When nonpressure sensitive strapping, twine, or cord is used for closure and reinforcement, it should encircle the package at least once girthwise and lengthwise over ILLUSTRATION 8 Strapping in center if gap is more than 5 inches Tape in center if gap is more than 5 inches the sides, ends and tops of rectangular containers and bundles. Twine and cord must be at least 20 pounds tensile strength and must be secured at an intersection at least once on each side. Strapping includes both metallic and nonmetallic banding and pressure sensitive filament tape. Loose strapping, especially metal, is not acceptable because it constitutes a hazard to employees and equipment and does not reinforce the container. (5) Staples and steel stitching. Staples and steel stitching are acceptable providing they are spaced not more than 21⁄2 inches apart and not more than 14 inches from the ends of the box. Boxes that do not meet these requirements may be made acceptable by application of a strip of three-inch-wide tape in the gap between the staples or by strapping to compensate for the gap in the staple closure. Illustration 8 shows staple and augmented staple closures. § 121.4 Marking. (a) General. Marking by the mailer must be by a material which is not readily water soluble of which can easily be rubbed off or smeared and will be sharp and clear at a distance of two feet. It is recommended that the name and address of the sender and addressee also be inserted within the package to aid in delivery if the address on the package is defaced. (b) Special markings. Special markings as identified shall be placed in an area below the postage and above the name of the addressee: (1) Fragile markings shall be applied to any package containing delicate items such as glass and electrical appliances. Identification of contents is not required. (2) Perishable markings shall be applied to any package which will degrade or decompose rapidly such as meat, produce, plants, or certain chemical samples. (3) Handling markings, such as DO NOT BEND, should be used only when contents are protected with stiffeners. (4) Words implying expedited handling, such as RUSH DO NOT DELAY, shall not be used on any package except those intended for shipment as special delivery or special handling mail. (5) Unauthorized labels which do not designate the address, nature of contents, or handling are not permitted. Obsolete markings will be obliterated. Containers improperly identified as to contents are not acceptable; e.g., a box marked as containing seafood which contains dry goods. (c) Marking surfaces. Marking methods or surfaces shall be of such type as to permit postal endorsements to be made by hand stamp, ball point pen, or Number 2 grade pencil. Package surfaces which will not retain an adhesive stamp, postage meter impression, ball point pen or pencil markings are not acceptable. § 121.5 Mailability. of (a) Acceptability. Acceptability packaging is a principal criteria of mailability. No item shall be packaged so that its contents may harm mail handling personnel or equipment. Fragile items must be packaged to withstand the mail processing and transportation environment. Heavy items must be braced and cushioned to prevent damage to other mail. Some general classes of items which cause a continuing problem due to packaging deficiencies are described in this section. Further information may be obtained from parcel post window clerks, dock foremen, and mailing require ments personnel. Requests for exceptions to the prohibitions set forth herein shall be submitted for a ruling to the Office of Mail Classification, Finance Department, U.S. Postal Service, Washington, D.C. 20260. (b) Publications. Publications and stationery-type items ranging from packages of several single sheets to hard back books weighing several pounds each constitute a major source of loose-inthe-mail items. Problems occur because of unrestrained, concentrated or shifting contents, and the use of containers, internal packaging, closures and reinforcements which are inadequate. Publications and stationery-type items exceeding one inch in depth or one pound in weight should not be accepted in envelopes. Publications in packages must be unitized by tying or banding or through the use of partitions or close fitting interior containers to prevent shifting. Illustration 9 gives several examILLUSTRATION 9 BEFORE WRAPPING ples of unitizing this type material. Boxes of publications must be adequately closed and should be reinforced with metal, nonmetallic or tape strapping. (c) Liquids. Liquids, particularly gallon containers with friction top closures, are a source of loss and damage to other mail and Postal equipment. As a general rule, containers of liquid with only friction top closures are not acceptable. Screw caps, soldering, clips or other means must be employed to effect closure. Glass and other breakable containers with a capacity of over 4 fluid ounces must be cushioned with an absorbent material sufficient to take up all leakage in case of breakage inside a sealed waterproof container. Containers of liquid with a capacity of over 32 fluid ounces shall not be acceptable for mailing unless cushioned as above and packaged within another sealed waterproof container, such as a can or plastic bag. The outer shipping container must be of sufficient strength to provide physical protection to the contents. Exceptions to this procedure must be submitted for a mailability ruling as prescribed in § 123.8 of this title. (d) Aerosols. Aerosol containers with inadequate friction cap closures, or other nonpositive means to prevent accidental discharge of contents, are a source of loss of contents and contamination to other mail. These cans must be so constructed as to preclude accidental discharge of contents in the mail. This may be accomplished through the use of recessed valves, screw thread caps, tape closures or other means of preventing discharge. (a) Write the name and the address clearly and legibly on one side only. See § 124.3 (c) (1) (xii) for exception on baby poultry. (b) Mail for delivery through a city delivery post office must include in the address the name and the street and number, or post office box number, or general delivery, or rural or star route designation (except simplified address mail as prescribed in § 122.4). Mail for customers on a rural route may be addressed to street names and numbers if this type of address has been approved (c) All mail should bear the name and address of the sender. For instructions concerning mail which must bear a return address, see: (1) Second-class mail in envelopes or wrappers-§ 125.2(f). (2) Fourth-class mail-§ 135.5 (a) (1). (3) Air parcel post-§ 136.6(a). (4) Mail of any class, when its return is desired-§ 122.3. (5) Registered mail-§ 161.3(a). (8) Matter bearing company permit imprints-§ 145.3(c). (d) Include the ZIP Code in all addresses and return addresses. See § 122.6. Example: (e) Attach a slip to articles enclosed in parcels showing the name and address of the sender and addressee. (f) Mail should be addressed to the specific place where the post office is to deliver it. Mail bearing both a street address and post office box number will be distributed for delivery in accordance with the address shown on the line immediately preceding the city and State of destination, unless the addressee has issued contrary instructions. The ZIP code shall correspond with the unit (box location or street address) to which delivery is to be effected. The requirements of this paragraph are also applicable to return addresses on mail matter. BUSINESS OR RESIDENCE LOCATION MAILING ADDRESS Henry Brown Route 3, Box 261 Mitchellville, MD 21109 Mr. John Jones 123 Maple St. P.O. Box 435213 Chicago, Illinois 60652 රිද්ර § 122.2 ZIP CODE CORRESPONDS TO THIS ADDRESS Arrangement of address. (a) The proper place for the address is in the lower right portion of the address area; postage (stamps, meter stamps or permit imprints) in the upper right corner; and return address of sender in the upper left corner. (b) Leave at least 31⁄2 inches of clear space, from top to bottom, at the right end of the address side of envelopes, folders, or labels. This space will be used for address, postage, postmark, and other prescribed endorsements such as airmail or special delivery. On large envelopes or mailing pieces, leave on the right end of the address side a clear rectangular space of not less than 3 by 44 inches or an equivalent area, for the address, stamps, |