1755.910—RUS specification for outside plant housings and serving area interface systems.
(a) Scope.
(1)
The purpose of this specification is to inform manufacturers and users of outside plant housings and serving area interface (SAI) systems of the engineering and technical requirements that are considered necessary for satisfactory performance in outside plant environments. Included are the mechanical, electrical, and environmental requirements, desired design features, and test methods for evaluation of the product.
(2)
The housing and terminal requirements reflect the best engineering judgment available at the present time and may be subject to change due to advances in technology, economic conditions, or other factors.
(3)
The test procedures described in this section are required by RUS to demonstrate the functional reliability of the product. However, other standard or unique test procedures may serve the same function. In such cases, RUS shall evaluate the test procedures and results on an individual basis.
(4)
The test procedures specified herein satisfy the requirements of housings as well as the requirements of terminals that may be installed within housings. Some of the requirements are interrelated to several tests designed to determine the performance aspects of terminals and are directly affected by testing required for housings. Therefore, the manufacturer should carefully review all the test requirements in order to develop a testing schedule that is comprehensive, efficient in terms of the number of test specimens required and can be accomplished in an orderly and logical sequence.
(5)
The specified tests may require special facilities to comply with Federal, State, or local regulatory requirements. Some test procedures are potentially hazardous to personnel because of the high voltages and mechanical forces involved. Safety precautions are necessary to prevent injury.
(6)
Underwriters Laboratories, Inc. (UL) 94, Tests for Flammability of Plastic Materials for Parts in Devices and Appliances, fourth edition, dated June 18, 1991, referenced in this section is incorporated by reference by RUS. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. A copy of the UL standard is available for inspection during normal business hours at RUS, room 2845-S, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from UL Inc., 333 Pfingsten Road, Northbrook, Illinois 60062-2096, telephone number (708) 272-8800.
(7)
The American Society for Testing and Materials Specifications (ASTM) A 109-91, Standard Specification for Steel, Strip, Carbon, Cold-Rolled; ASTM A 153-82 (Reapproved 1987), Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware; ASTM A 366/A 366M-91, Standard Specification for Steel, Sheet, Carbon, Cold-Rolled, Commercial Quality; ASTM A 525-91b, Standard Specification for General Requirements for Steel Sheet, Zinc-Coated (Galvanized) by the Hot-Dip Process; ASTM A 526/A 526M-90, Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) by the Hot-Dip Process, Commercial Quality; ASTM A 569/A 569M-91a, Standard Specification for Steel, Carbon (0.15 Maximum, Percent), Hot-Rolled Sheet and Strip Commercial Quality; ASTM A 621/A 621M-92, Standard Specification for Steel, Sheet and Strip, Carbon, Hot-Rolled, Drawing Quality; ASTM B 117-90, Standard Test Method of Salt Spray (Fog) Testing; ASTM B 539-90, Standard Test Methods for Measuring Contact Resistance of Electrical Connections (Static Contacts); ASTM B 633-85, Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel; ASTM D 523-89, Standard Test Method for Specular Gloss; ASTM D 610-85 (Reapproved 1989), Standard Test Method for Evaluating Degree of Rusting on Painted Steel Surfaces; ASTM D 822-89, Standard Practice for Conducting Tests on Paint and Related Coatings and Materials using Filtered Open-Flame Carbon-Arc Light and Water Exposure Apparatus; ASTM D 1535-89, Standard Test Method for Specifying Color by the Munsell System; ASTM D 1654-92, Standard Test Method for Evaluation of Painted or Coated Specimens Subjected to Corrosive Environments; ASTM D 1693-70 (Reapproved 1988), Standard Test Method for Environmental Stress-Cracking of Ethylene Plastics; ASTM D 2197-86 (Reapproved 1991), Standard Test Method for Adhesion of Organic Coatings by Scrape Adhesion; ASTM D 2247-92, Standard Practice for Testing Water Resistance of Coatings in 100% Relative Humidity; ASTM D 2565-92, Standard Practice for Operating Xenon Arc-Type Light-Exposure Apparatus With and Without Water for Exposure of Plastics; ASTM D 2794-92, Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact); ASTM D 3928-89, Standard Test Method for Evaluation of Gloss or Sheen Uniformity; ASTM D 4568-86, Standard Test Methods for Evaluating Compatibility Between Cable Filling and Flooding Compounds and Polyolefin Cable Materials; ASTM G 21-90, Standard Practice for Determining Resistance of Synthetic Polymeric Materials to Fungi; and ASTM G 23-90, Standard Practice for Operating Light-Exposure Apparatus (Carbon-Arc Type) With and Without Water for Exposure of Nonmetallic Materials, referenced in this section are incorporated by reference by RUS. These incorporations by references were approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 7 CFR part 51. Copies of the ASTM standards are available for inspection during normal business hours at RUS, room 2845-S, U.S. Department of Agriculture, Washington, DC 20250-1500, or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html. Copies are available from ASTM, 1916 Race Street, Philadelphia, Pennsylvania 19103-1187, telephone number (215) 299-5585.
(b) General information.
(1)
Outside plant housings are fabricated of either metallic or nonmetallic materials in different sizes and configurations to suit a variety of applications. The purpose of a housing is to protect its contents from environmental elements, rodents, insects, or vandalism and unauthorized access. Housings are designed with internal brackets for accommodating splicing, bonding and grounding connections, cable terminals, cross-connect facilities, load coils, and optical and electronic equipment.
(2)
Pedestals are housings primarily intended to house, organize, and protect cable terminations incorporating terminal blocks, splice connectors and modules, ground lugs and load coils. Activities typically performed in a pedestal are cable splicing, shield bonding and grounding, inductive loading, and connection of subscriber drops.
(3)
Serving area interface (SAI) cabinets are housings intended to perform some of the same functions as pedestals but are primarily intended to serve as the connecting terminal between feeder cable and distribution cables.
(4)
Outside plant housings shall be manufactured in accordance with National Electrical Code (NEC) requirements, Underwriters' Laboratories (UL) requirements, Department of Labor, Occupational Safety and Health Administration Standards (OSHA), and all other applicable Federal, State, and local requirements including, but not limited to, statutes, rules, regulations, orders, or ordinances otherwise imposed by law.
(c) General documentation requirements—
(1) Installation and maintenance instructions.
Each product shall have available a set of instructions designed to provide sufficient information for the successful installation of the housing, cables, auxiliary equipment, and the associated splice preparation. The instructions shall be of sufficient size to be easily read and shall be printed using waterproof ink. Pedestal instruction sheets shall include a list of miscellaneous replacement parts that may be purchased locally. SAI systems shall be supplied with complete instructions for installation and use.
(ii)
When requested by RUS, or an RUS borrower, the manufacturer shall prepare a training package for the purpose of training technicians in the use and installation of the product and its auxiliary equipment.
(iii)
The manufacturer shall provide ordering information for repair parts. Repair parts shall be obtainable through a local distributor or shall be easily obtainable. Information describing equivalent parts and their sources should be provided for those parts that may also be obtained from other sources.
(2) Quality assurance.
The manufacturer shall demonstrate the existence of an ongoing quality assurance program that includes controls, procedures, and standards used for vendor certification, source inspection, incoming inspection, manufacture, in process testing, calibration and maintenance of tools and test equipment, final product inspection and testing, periodic qualification testing and control of nonconforming materials and products. The manufacturer shall maintain quality assurance records for five years.
(3) RUS acceptance applications.
(i)
The tests described in this specification are required for acceptance of product designs and major modifications of accepted designs. All modifications shall be considered major unless otherwise declared by RUS. The tests are intended to show the inherent capability of the manufacturer to produce products which have an expected service life of 30 years.
(A)
Submit an original signature certification that the product complies with each section of the specification;
(E)
Provide a complete set of instructions, recommendations for equipment organization and splicing;
(G)
Provide a certification that the product does or does not comply with the domestic origin manufacturing provisions of the “Buy American” requirements of the Rural Electrification Act of 1938 (52 Stat. 818);
(iii)
Each requirement of this section must be addressed in submissions for acceptance. The designation N/A may be entered when the requirements do not apply.
(iv)
Acceptance requests should be addressed to: Chairman, Technical Standards, Committee “A” (Telephone), Telecommunications Standards Division, Rural Utilities Service, Washington, DC 20250-1500.
(d) Functional design criteria for housings—
(1) General requirements.
The functional requirements for housings concern materials, finishes, environmental factors, and design features that are applicable to most above ground housings used in the outside plant.
(ii)
Housings shall be of sufficient size to permit easily managed installation, operational, testing, and maintenance operations. The general shape of outside plant housings is usually comparable to that of a rectangular column or cylinder, with the shape of any particular housing being left to the manufacturer's discretion. Each design is subject to acceptance by RUS.
(2) Housing types and capacities.
(i)
Housings used in outside plant are either the smaller housings generally known as pedestals or larger housings known as equipment or splice cabinets. Both categories may have designs intended for stake mounting, pole mounting, or pad mounting.
(ii)
The classifications of pedestals are the general purpose channel Type (H) and the dome Type (M). The Type H pedestal has either front only access or back and front access while the Type M pedestal has top only access. Pedestals are further designated as follows:
| Stake mounted | Type | Pole mounted | Pole mounted (extra high) |
|---|---|---|---|
| BD3 | H | BD3A | |
| BD4 | H | BD4A | |
| BD5 | H | BD5A | |
| BD7 | H | BD7A | |
| BD14 | M | BD14A | BD14AG |
| BD15 | M | BD15A | BD15AG |
| BD16 | M | BD16A | BD16AG |
(iii)
The minimum volume associated with the pedestal designations shall be as shown in the following table:
| Pedestal 1 housing designation | Minimum volume | |
|---|---|---|
| Cubic centimeters cm 3 | (Cubic Inches) (in.3) | |
| BD3, BD3A 2 | 9,000 | (550) |
| BD4, BD4A 2 | 15,000 | (900) |
| BD5, BD5A 2 | 35,000 | (2,100) |
| BD7( 2 ) | 72,000 | (4,400) |
| BD14, BD14A, BD14AG 3 | 9,000 | (550) |
| BD15, BD15A, BD15AG 3 | 27,000 | (1,600) |
| BD16, BD16A, BD16AG 3 | 38,000 | (2,300) |
| Note 1: Housings designed for unique purposes will be evaluated on a case-by-case basis. | ||
|
Note 2: For Type H pedestals, the minimum volume is that space as measured 5 centimeters (cm) (2 inches (in.)) below the top of the housing to a point 40 cm (16 in.) above the bottom of the lower cover plate.
Code of Federal Regulations
751
|
||
| Note 3: The minimum volume of the Type M pedestals shall be the space within the dome measured from the lower edge of the dome to a point 5 cm (2 in.) from the top. | ||
(iv)
Equipment cabinets intended for use as SAI housings shall be assigned size designations according to their maximum pair termination capacities. The capacity will vary depending on the type of terminating equipment used. SAI cabinets shall be suffix designated with an “A” for pole mounting, “X” for pad mounting, and “S” for stake mounting.
(v)
Large pair count splice cabinets are classified according to their splice capacity. Approximately 48 cm 3 (3.0 in. 3) of splice area per pair straight spliced shall be permitted.
(vi)
The minimum volume associated with large pair count splice cabinets shall be as shown in the following table:
| Splice cabinet 1 designation | Minimum volume | Maximum splice capacity (pairs) | |
|---|---|---|---|
| (cm.3) | (in.3) | ||
| BD6000 | 295,000 | (18,000) | 6,000 |
| BD8000 | 393,000 | (24,000) | 8,000 |
| BD10000 | 491,000 | (30,000) | 10,000 |
| Note 1: Additional sizes of splice cabinets shall be considered by RUS on a case-by-case basis. | |||
(3) Design and fabrication requirements for housings.
(i)
Type H pedestal housings may consist of an enclosed channel incorporating an integrally mounted stake that serves as a backplate, or they may be designed for universal mounting on stakes or poles. The body of the housing shall have two major components; an upper cover and a base cover. The upper cover shall have a top, front and back plate with the front cover removable to permit entry and provide increased work space. The base cover shall consist of a front plate and back plate. The base cover back plate may be an extension of the upper back plate cover.
(ii)
Type M pedestal housings shall consist of a one piece upper sleeve designed to fit over the base cover trapping air to prohibit water from entering the splice area when installed in locations prone to temporary flooding. Pedestals designed to be mounted extra high on poles for locations susceptible to deep snow shall have a bottom close-off option available to prohibit the ingress of birds, rodents and insects.
(iii)
The external housing components on all outside plant housings shall provide reasonable protection against accidental removal or vandalism. Housings shall be equipped with a cover plate retaining bolt and cup washer that may be opened only with an industry accepted socket type can wrench. Housings may be equipped with provisions to allow the purchaser to install a padlock.
(iv)
Installed housings shall resist the disassembling force of frost heaving applied to the bottom of ground line cover plates. The base cover must remain stationary to stabilize the contents of the housing cavity.
(v)
In an effort to provide protection against dust penetration, blowing snow, rain, and ultraviolet light degradation of internal components, all mechanical gaps shall be restricted. The use of seals, overlaps, gaskets, and/or dovetailing is required to assure satisfactory protection of housed equipment.
(vi)
Knockouts, cutouts, or notches designed to accommodate aerial service drops shall not be permitted. A design option for housings intended to accommodate service drops shall include a separate channel or equivalent in the base cover to allow future additions of service drops without the removal of gravel or the moisture barrier in the base of the housing. Service wire channels must be designed to prevent the entry of birds, reptiles, rodents and insects.
(vii)
Minimal venting of SAI housings may be necessary to relieve internal pressure and condensation.
(viii)
There shall be no aluminum housing components that will become buried in the soil when the housing is properly installed.
(ix)
Housing components may be assembled using rivets, welds, glue, bolts and nuts, or other techniques suitable for the materials involved.
(x)
Housings and their components that require field assembly must be capable of being assembled with tools normally available to outside plant technicians.
(xi)
Hinged doors on SAI housings and large pair count splice housings shall be equipped with a device that restrains the doors in the open position.
(xii)
Outside plant housings shall be free of sharp edges, burrs, etc., that could present a safety hazard to personnel involved in installation and use of the product or to the general public. Surfaces inside housings must not allow pinching of conductors during installation of cover plates or the opening and closing of doors.
(xiii)
A ground line mark shall be provided, approximately 15 cm (6 in.) below the top edge of the housing base cover plate on housings intended for ground level mounting. Base cover plates shall have a minimum height of 31 cm (12 in.).
(xiv)
Any housing, which weighs in excess of 91 kilograms (kg) (200 pounds (lb)), including its contents, shall be equipped with lifting brackets for attaching hoisting cables or chains.
(xv)
Housing stakes shall be a minimum of 107 cm (42 in.) in length. If fabricated from steel, they shall have a minimum thickness of No. 13 gauge as measured according to American Society for Testing and Materials (ASTM) A 525-91b. Stakes shall be formed into a “U” channel with a minimum depth of 2 cm (0.75 in.). The stake shall be a single part of suitable design strength for driving 91 cm (36 in.) into the soil with hand tools without damage such as bending or warping. The stake shall have adequate mounting holes having a minimum separation of 15 cm (6 in.) for mounting the housing baseplate. The stake material must resist corrosion and deterioration when exposed to soil and atmospheric conditions.
(xvi)
The housing design must permit a logical progression of installation steps that would normally be encountered in typical field installations.
(xvii)
Provisions for attaching housings to stakes, poles, walls, other housings, or pads shall be provided for each design intended for those purposes. Locations of holes for mounting attachments may be provided by knockouts on above ground components. Mounting hole locations for below ground components may be predrilled.
(xviii)
Pole mounting hardware shall provide at least 1.3 cm (0.5 in.) clearance from the pole to the housing. Pole mounting brackets shall accommodate the wide range of pole sizes used in the telephone industry.
(xix)
Pad-mounted housings shall have hardware available for anchoring the housing base to the pad. A template may be provided to assist in the location of mounting attachment details for pad preparation.
(xx)
Housings equipped with stub cables shall have strain relief devices to permit shipping and handling of the housing without damage to the housing or stub cables. Only RUS accepted cable shall be used for stub cables. The cable manufacturer's recommendations concerning minimum bend radius shall be observed. The minimum bend radius for most copper cables is 10 times the cable diameter.
(xxi)
Cable supports shall be provided near the top of the ground line cover and other appropriate locations within the housing to provide cable stability consistent with the intended use and capacity of the housing. Cable supports shall be capable of holding a minimum load of 23 kg (50 lb).
(xxii)
An adequate supply of nonmetallic retainer clips or tie wraps capable of supporting a minimum load of 23 kg (50 lb) shall be provided with the housing. Adequate spaces for installation of the clips or tie wraps must be provided on the housing backplate and cable supports.
(xxiii)
Housing chambers designed for splicing operations shall be equipped with insulated supporting straps or rods suitable for supporting splice bundles. The insulation on the straps or rods shall extend for the entire length of the device and shall have a dielectric strength of 15 kilovolts (kv) direct current (dc) minimum. Housings having an “H” frame design where both front and rear covers may be removed may incorporate insulated tie bars to be used as cable supports.
(xxiv)
Housings designed to contain equipment in addition to splices shall be equipped with a device for physically separating the splice area from the service area of the housing.
(xxv)
A dielectric shield rated at 15 kv dc shall be provided to enclose the cable splice area. The shield shall extend from the lower cable supports to within 2.5 cm (1 in.) of the top of the housing. The shield shall be equipped with Velcro or equivalent fastening devices designed to hold the shield in both the open or closed positions. The fastening devices shall extend along the entire vertical edge of the dielectric shield.
(xxvi)
Mounting arrangements for a variety of terminal blocks and other equipment shall be provided by means of good housekeeping panels or other devices that may enhance the service aspect of the housing.
(xxvii)
Housings designed for SAI cabinets may be shipped with terminal blocks installed and stub cables attached. If this option is exercised, the stub cables and terminal blocks must be RUS accepted. In all cases, SAI cabinets must be equipped with appropriate mounting devices for installing the peripheral equipment required for a serving area interface.
(xxviii)
SAI cabinets shall be designed to provide physical separation between the splicing area and the area provided for running cross-connect jumpers.
(xxix)
SAI cabinets and large splice housings must have an external feature for attaching a padlock to prevent unauthorized entry.
(xxx)
Each housing shall have a tinned or zinc electroplated copper alloy or equivalent connector plate or bar to be used for terminating ground and cable shield bond connections. The device shall be equipped with captive studs and nuts with captive lock washers designed for attaching 6 American Wire Gauge (AWG) copper bonding harness wire or braid and a 6 AWG copper ground wire. Connector plates shall be equipped with enough studs and nuts to provide individual connections equivalent to the maximum number of cable sheaths recommended for the housing. Housings shall incorporate design features that enable the field installation of at least one additional connector plate for service conditions that require numerous connections. A bonding and grounding system capable of providing support and strain relief for service wires shall be provided for housings intended for use as distribution points. The bonding system shall be designed to provide sheath continuity as cable and service wires are installed, and prior to any other operation being performed. The bonding arrangement shall provide electrical continuity between all bonds and the ground connector plate. The bonding and grounding arrangement shall permit the lifting of individual cable ground connections for testing and cable locating activities without jeopardizing the grounding potential of other cables that may enter the housing. The bonding and grounding system shall be capable of conducting a current of 1000 amperes for at least 20 seconds.
(4) Warning sign.
(i)
A buried cable warning sign shall be securely attached to the outside of each housing. The lettering information on the sign shall be permanent.
(ii)
For pedestals, the sign shall be centered horizontally on the front cover and the top of the sign shall be not more than 10 cm (4 in.) from the top of the housing.
(iii)
For SAI cabinets, the sign shall be centered horizontally and vertically on the door. If there are two doors, the sign shall be mounted on the left door.
(iv)
Deviations from warning sign location requirements are permitted only for housing design constraints. Alternate sign locations will be considered by RUS.
(5) Housing materials.
(i)
Materials used in housings shall present no environmental or safety hazard as defined by industry standards or Federal, State, or local laws and regulations. Figure 1 is as follows:
Code of Federal Regulations
Code of Federal Regulations
754
(ii)
All materials are required to have fire resistance ratings consistent with recognized industry standards. External materials must be flame resistant.
(iii)
All materials used in the manufacture of housings or component parts must achieve the required strength properties, resist deterioration when exposed to outdoor conditions, and be acceptable to RUS for the specific application. New materials or materials not familiar to the RUS staff shall be supported by test and performance data which demonstrates their suitability for the intended use.
(iv)
Nonmetallic housing materials shall have a fungus growth rating no greater than one according to ASTM G 21-90.
(v)
Metallic components shall be either corrosion resistant or protected against corrosion and must not produce galvanic corrosion in wet or humid conditions on other metals that may be present in the housing environment.
(vi)
Mill galvanized steel used in the manufacture of housings shall comply with the appropriate requirements of one of the following standards:
(vii)
Hot rolled steel shall comply with the appropriate requirements of one of the following standards:
(viii)
Cold rolled steel shall comply with the appropriate requirements of one of the following standards:
(ix)
Steel parts used for internal housing brackets shall be hexavalent chromate coated or zinc plated in accordance with ASTM B 633-85.
(x)
Hardware items used for assembling or fastening housing components shall be 300 series or passivated 400 series stainless steel or hot dip galvanized in accordance with ASTM A l53-82 (1987). Other materials will be considered by RUS on an individual basis.
(xi)
Aluminum components shall be fabricated from alloy types 5052 or 6061 or other types that have been recognized as having acceptable corrosion resistance and formability and weldability features.
(xii)
Nonmetallic parts must be resistant to solvents and stress cracking and shall be compatible with metals and other materials such as conductor insulations and filling compounds used in the manufacture of cable. Plastic materials must be noncorrosive to metals and resist deterioration when exposed to industrial chemical pollutants, ultra-violet rays, road salts, cleaning agents, insecticides, fertilizers, or other detrimental elements normally encountered in the outdoor environment.
(xiii)
Housing door seals and gaskets may be manufactured from rubber or synthetic rubber-like elastomer materials. Seals and gaskets shall exhibit a high degree of weatherability with an effective life of at least 30 years in the outdoor environment. The material shall be tear resistant and have a low compression set.
(6) Housing finish requirements.
(i)
All interior and exterior surfaces of housings shall be free from blisters, wrinkles, cracks, scratches, dents, heat marks, and other defects.
(ii)
There shall be inherent design provisions to prevent objectionable deterioration of the housing such as rusting, exposure of fiber or delamination. Secondary protection, such as galvanizing over steel per ASTM A 526/A 526M-90 or anodizing over aluminum, shall be provided to ensure reliability over the projected 30 year design life of the housing.
(iii)
Painted metal housings shall have a minimum gloss of 60 (60 °specular) in accordance with ASTM D 523-89.
(iv)
All painted surfaces shall have a uniform color and texture in accordance with ASTM D 3928-89. Nonmetallic housings shall meet recognized industry standards concerning optical appearance for gloss and haze as applicable for the material.
| Color | Standard |
|---|---|
| Gray-Green | Munsell 6.5 GY 6.03/1.6 |
| Munsell 4.4 GY 6.74/1.5 | |
| Green | Munsell 8.8 G 2.65/5.3 |
| Orange | Federal Standard 595A |
| Color Number l2246 | |
| Munsell 0.15YR 5.26/13.15 | |
| Chocolate | Munsell 5.27YR 2.40/2.60 |
| Color Number 835 |
(7) Installation requirements.
(i)
The design of the housing must provide for a logical and normal installation sequence, i.e., excavation, installation of a foundation or base and anchoring devices, addition of hardware, installation and bonding of cables, splicing, addition of service, and final closing.
(ii)
No special tools or equipment other than that usually carried by outside plant technicians and construction crews must be required for installation of the housing. Security devices are the exception to this requirement.
(iii)
Installation hardware shall maintain housings in an erect and stable position when subjected to normal storm loads. Pad-mounted designs must accommodate precast or cast-in-place reinforced concrete or other suitable prefabricated material. Brackets, inserts for fastening, conduit openings, or other items necessary for a pad-mounted installation must be provided. The manufacturer shall provide detailed drawings or a template for locating inserts, conduit openings, or slots for cast-in-place pad construction.
(e) Performance criteria and test procedures for housings—
(1) General information.
The housing manufacturer shall perform adequate inspections and tests to demonstrate that housings and housing components comply with RUS requirements.
(ii)
Testing shall be performed at a room temperature of 24±3 °C (75±5 °C). Temperatures for testing performed at other than room temperature shall be determined as near the center of the product under test as practical.
(2) Description of test housing.
(i)
Each distinctly designed and configured family of housings intended to perform a particular function shall be tested.
(ii)
The typical test sample shall consist of the exterior housing components such as covers, backplates, good housekeeping panels, cap assembly, anchor posts, decals, etc. Interior components must include the bonding and grounding hardware for cables and service wires and the dielectric shield. The housing may include terminal blocks or cross-connect modules, cable splices, or the typical outside plant equipment the housing is designed to contain and protect.
(3) Environmental requirement for housings—
(i) Thermal shock.
The test housing shall be placed in a test chamber and exposed to the temperature cycle of Figure 2 for five complete cycles. The step function nature of the temperature changes may be achieved by insertion and removal of the test housing from the chamber. The soak time at each temperature shall be four hours. The housing shall be removed from the test chamber at the conclusion of the five-cycle period. After the test housing temperature has stabilized to room temperature, the housing must be inspected for deterioration of materials and satisfactory operation of mechanical functions. Figure 2 is as follows:
Code of Federal Regulations
Code of Federal Regulations
757
(ii) Thermal shock and humidity.
The test housing shall be placed in an environmental test chamber at 95 ±3 percent (%) relative humidity (RH) and temperature cycled per Figure 3 for a period of 30 days. At the end of the test there shall be no rust or corrosion of any closure components. Minor corrosion due to surface scratches, nicks, etc. is permitted. If the closure is made of a nonmetallic material, there shall be no signs of degradation. Figure 3 is as follows:
Code of Federal Regulations
Code of Federal Regulations
758
(iii) Humidity and condensation.
Test panels shall be placed in an environmental chamber and subjected to 1,008 hours (42 cycles) of exposure per ASTM D 2247-92. One cycle consists of 24 hours of 100% humidity (with condensation on the panels) at a cabinet temperature of 38±1 °C (100±2 °F) and an ambient temperature of 25±1 °C (77±2 °F) without heat input. Upon completion of cycling, the test panels shall be subjected to an 11 newton-meter (N-m) (100 pound-inches (lb-in.)) impact test using the Gardner-Impact Tester or equivalent. Test panels shall show no substrate or coating cracking or loss of coating adhesion on either side.
(iv) Weatherability.
Three test panels shall be tested for weatherability in accordance with the appropriate procedures of either ASTM D 822-89 or ASTM G 23-90. Total exposure time shall be a minimum of 800 hours. Failure is defined as fading, cracking, blistering, or delamination on any of the three test panels.
(v) Low temperature durability.
Low temperature durability shall be proven by exposing the three test panels from (e)(3)(iv) of this section to at least 25 continuous cycles of the following test sequence:
(A)
To insure complete saturation of the three test panels, soak them for 96 hours in a container of distilled water 22±2 °C (71.6±4 °F);
(B)
Lower the temperature of the water and the immersed test panels to −28±2 °C (−18.4±4 °F) and stabilize for 24 hours;
(D)
Repeat the procedure 24 times. Any cracking, crazing, deforming, or delaminating on any of the three test panels shall be considered a failure; and
(E)
Remove the samples from the water and impact test the three panels by delivering a force of 11.3 N-m (100 lb-in.) using a Gardner-Impact Tester to each specimen at 71, 22, and −28±2 °C (159.8, 71.6, and −18.4±4 °F), after stabilizing them at those temperatures for at least two hours. Visual inspection shall reveal no deformation or perforations on any of the test panels.
(vi) Corrosion resistance.
Corrosivity shall be tested in accordance with the requirements of ASTM B 117-90. Both scribed and unscribed panels shall be evaluated following the procedures of ASTM D 1654-92. Scribed panels shall have a rating of at least six, following 500 hours of exposure to salt fog, and the unscribed panels shall have a rating no lower than 10, after 1,000 hours exposure. Visual rust inspection shall confirm no more than 0.03% rusting (rust grade 9) of the surface area of the test sample when evaluated in accordance with ASTM D 610-85(1989). The unscribed samples shall be impacted with an 11.3 N-m (100 lb-in.) force, using a Gardner-Impact Tester or equivalent. Visual inspection of the impacted samples shall reveal no loss of adhesion between the base material and the coating or cracking at the finish on the test panels.
(vii) Fungi resistance.
Fungi resistance of nonmetallic housing materials shall be tested according to the procedures of ASTM G 21-90. Any rating greater than one shall be considered a failure.
(viii) Stress crack resistance.
The stress cracking characteristics of nonmetallic housing components shall be tested in accordance with ASTM D 1693-70 (Reapproved 1988). The tests shall be performed at 49±2 1/2 C (120±4 1/2 F) for 14 days and exposed to the following materials:
(ix) Chemical resistance.
(A)
Chemical resistance shall be determined by immersing representative nonmetallic material samples in each of the following solutions for 72 hours at 22±2 °C (71.6±4 °F):
(1) 3% sulfuric acid;
(2) 100 parts