Industry Standards and Load Ratings of Enclosures by Oldcastle Enclosure Solutions Team Presenter: Ravi Devalapura, Ph.D. MAG Specification and Details Committee Water /Sewer Working Group Meeting Phoenix, March 15, 2016

Objectives This presentation is designed to provide basic understanding on: What type of loads act on an enclosures after installation Different load ratings & standards used in the industry How to choose applicable standards and load factors (their words..) This coarse is designed to provide basic understanding on: What type of loads act on an enclosure after the installation and what factors of safeties involved Different load ratings & standards used in the industry How to test boxes for wheel loading and what factors of safety are involved At the end of this coarse, you will understand why load ratings are important and how to use right box to right applications. Intended audience include Sales, CSRs, Engg team, and anyone who wish to learn load ratings on enclosures. (Jason’s words) This coarse will provide a basic understanding on: The effect of loads on enclosures Safety factors involved Load ratings Industry standards Testing loads on enclosures Which enclosures to use for various applications

Units and Terminology PSI Pounds per square inch PSF Pounds per square foot PCF Pounds per cubic foot Design Load Load at which product is repeatedly applied safely Test Load Load at which product is considered to have passed the test requirement Operating an electric switch is like turning on a water faucet. Behind the faucet or switch there must be a source of water or electricity with something to transport it, and with a force to make it flow. In the case of water, the source is a reservoir or pumping station; the transportation is through pipes; and the force to make it flow is provided by a pump. For electricity, the source is the power generating station; current travels through electric conductors (wires); and the force to make it flow - voltage, measured in volts, is provided by a generator. Resistance - Dry skin has a fairly high resistance, but when moist, resistance drops radically, making it a ready conductor. - Measured in ohms. Use extra caution when working with electricity when water is present in the environment or on the skin. Pure water is a poor conductor, but small amounts of impurities, such as salt and acid (both are contained in perspiration), make it a ready conductor. Yield Point on a stress/strain curve where the applied load no longer increases as deflection continues Ultimate Load Point where increasing load results in exceeding elastic limit of a material Factor of Safety Ultimate load/design load. Typically a factor of 1.5-3.0 is commonly used Deflection Compression or bending measured in inches

Loads and Load Types Loads Enclosures are subjected to different loads during their service life. These loads come from pedestrian, vehicular traffic, soil pressure, surcharge, and fluid pressure. The forces acting on the walls and lid of enclosure vary depending on the magnitude and the relative location of the enclosure with load.

Loads and Load Types There are different types of loads or pressures which act on the enclosure unit. Loads vary depending on enclosure location and what the enclosures are designed to withstand. Structural Environmental Pedestrian loads Vehicle loads Soil pressure Surcharge Pressure Fluid pressure Impact Loads Chemical resistance UV Testing Moisture effect Freeze and Thaw Coefficient of Friction Flammability test Other…

Standards and Specifications SCTE 77 Specific to enclosures used for holding equipment used for telecommunication and other low voltage apparatus. SCTE Society of Cable Telecommunications Engineers WUC Western Underground Committee ASTM American Society for Testing and Materials AASHTO American Association of State Highway and Transportation WUC GUIDE Covers requirements to non-concrete materials and four specific sizes. ASTM C857 Load ratings for precast concrete utility structures.

Standards and Specifications AASHTO For highways and bridges with deliberate vehicular traffic Telcordia GR-902-CORE Issue 2 2013 Used mainly by the Telecommunication industry and differs with SCTE 77 in many test procedures SCTE Society of Cable Telecommunications Engineers WUC Western Underground Committee ASTM American Society for Testing and Materials AASHTO American Association of State Highway and Transportation Enclosure Manufacturers Manufacturer Standards Enclosure manufacturers have developed specifications based on their proprietary design and experience

Industry Standards - SCTE 77 2013 Covers conformance tests and requirements for enclosures containing telecommunication and other low voltage apparatus Environmental Tests and Structural Load Tests Test method are well defined with test set up figures for different Tier ratings Some tests referred to follow ASTM standards and others are covered with a test procedure All load ratings and deflection limits are listed in Tables (shown)

Industry Standards - Western Underground Committee (WUC) Guide 3.6 Applicable to non-concrete materials (plastic, polymer concrete) Only four common sizes are covered Includes both structural and material requirements Provisions are similar to SCTE 77 but with less clarity Provides details on testing criteria WUC Guide is a “Guide”… NOT a “Standard”

Industry Standards - ASTM C857 - 11 Standard Practice for Minimum Structural Loading for Underground Precast Concrete Utility Structures Provides vehicle and pedestrian live and dead loads. Covers how to calculate applicable loads, load distribution, and lateral pressures from soil. Categorizes these minimum designs into designations as in Table below.

Industry Standards - AASHTO American Association of State Highway & Transportation Officials Very detailed document for designing bridges and highways Developed by Departments of Transportation officials Takes into consideration a moving vehicle so it’s also specific to enclosures that will be in major traffic areas. Two main categories: “H” for two-axel trucks and “HS” for tractor trucks Category: H H10, H15, H20 Category: HS HS10, HS15, HS20

Industry Standards – Telcordia GR-902-CORE Issue 2 2013 Allows both metallic and nonmetallic materials for the handholes Load tests are divided in to four categories and are color coded. Lateral load cycles varies with size and a long-term (90 days) test is included Requires extensive material- specific tests to meet the requirements

Industry Standards – Manufacturer Standards Each manufacturer has developed their own standards based on experience, design, and proven applications. Larger players offer different products and load ratings based on the application Some specifications are based on empirical designs and some are well engineered. The product data sheets can be confusing with limited information One need to understand the performance in detail before choosing the right solution Manufacturer Specification

Load Rating Comparison Chart Performance Category Gross Vehicle Weight (lb) Max Wheel Load (lb)* Design Load (lb) Test Load (lb) Specification Load Classification Light Duty / Pedestrian Only -- 300 psf 2,000 3,000 ASTM C 857 SCTE 77 Telcordia GR-902 A-0.3 Walkways Light Duty, Pedestrian Category I, Light Duty Medium Duty / Non-Deliberate (Incidental) Traffic 19,500 40,000 7,800 16,000 5,000 8,000 15,000 10,400 12,000 7,500 16,640 22,500 24,960 WUC Guide 3.6 ASTM C857 Tier 5 Tier 8 Category II, Medium Duty A-8 (HS-10), Light Traffic Tier 15 In Shoulder or sidewalks A-12 (HS-15), Medium Traffic Category III, Heavy Duty Heavy Duty / Non-Deliberate (Incidental) Traffic 33,750 Tier 22 Category IV Designated Roadway Traffic 72,000 20,800 33,280 36,400 AASHTO A-16 (H-20) HS-20 * Max wheel load = 40% of GVW

Final Review…. There are several industry standards and guidelines available for enclosures. Load criteria and safety factors are not uniform between industry specifications. There are no industry standards for water market applications. Most municipalities spec call for pedestrian to 20K max loading. “H20” and “20K” do not represent equal performance. WUC, Guide 3.6 specification applies to non-concrete enclosures. Though some products are rated equal, there may be difference in how they were tested and what protocols used.