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Electronic Truck Weighing System Technical Specification

Table of Contents

1. Purpose
2. Scope
3. Related Documents
4. General Information
5. Requirements for Weighing System Basic Components and Installation
6. Requirements for Weighing System Optional Components and Installation
7. Painting
8. Inspection Requirements
9. Preparation for Shipment
10. Spare Parts and Service
11. Documentation Requirements
12. Bid Proposal Information

1.  What is Purpose of this article?  This article is about  minimum technical specification requirements for electronic truck weighing systems.

minimum technical specification requirements for electronic truck weighing systems

2. Electronic Truck Weighing System Technical Specification

  1. This specification applies to all truck weighing system installation and used for “on-scale” truck loading as well as conventional “off-scale” loading.
  2. This specification applies only to truck weighing systems using all electronic load cell weight measurement.
  3. Options and requirements will be based on project-specific documents.

4.  Electronic Truck Weighing System Scope of Work

3.  Electronic Truck Weighing System Related Articles and Standards

Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F)

National Institute of Standards and Technology (NIST)

Handbook H-44  –  Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices

Structural Steel Painting Council (SSPC)

SP-1   Solvent Cleaning

SP-6   Commercial Blast Cleaning

4. Electronic Truck Weighing General Information

4.1      Truck Information

    1. Maximum truck weight (tractor plus filled trailer) will be specified in the project-specific documents.
    2. Maximum truck length (tractor plus trailer) will be specified in the project-specific documents.

4.2      Location

    1. The weigh system will be installed at the location specified in the project-specific documents.
    2. The weighbridge will be located outdoors unless otherwise stated in the project-specific documents.
    3. The system indicator-controller, printer, and related equipment will be located as specified in the project-specific documents.
    4. The system supplier shall ensure that the weighing system is according to all national, provincial, and local codes, regulations, standards, and specifications applicable at the installation site location.

4.3      Weighing System Operations

    1. A description of how the weighing system will be used and how its components shall be configured will be given in the project-specific documents.
    2. This description will cover such information as the following:
      • Truck loading procedure to be used (that is, “on” weighbridge versus “off” weighbridge loading).
      • Location of the person operating the weighing system (that is, truck driver inside the truck cab versus truck driver or other person from a space remote from the weighbridge). This information will also define the location of various components of the weighing system.
      • Method used to input truck/driver information to the weighing system (that is, manual “keyed-in” information versus automatic “swipe card” input).
    3. A listing of the optional items required for a given weighing system will be given in the project-specific documents. A full list of options available is in paragraph above.

4.4  Weighbridge Information

    1. The nominal rated weight capacity of the weighbridge assembly shall be according to the project-specific documents.
    2. The nominal length of the assembled weighbridge sections shall be according to the project-specific documents.
    3. The weighbridge will be located in a shallow pit foundation unless otherwise specified in the project-specific documents.
    4. The weighbridge shall perform as a single weighing platform.

5. REQUIREMENTS FOR WEIGHING SYSTEM BASIC COMPONENTS AND INSTALLATION

5.1      General

Followings are general technical points for Electronic Truck Weighing System

  1. This article is about minimum Company requirements for an electronic truck weighing system.
  2.  All equipment, materials, and workmanship shall be according to this technical specification and the project-specific documents. Any exceptions must be stated in writing by the system supplier and approved in writing by Company before it may be used in the system.
  3. The weighing system shall be constructed, installed, tested, and approved such that it can be used for legal trade in the country and locality of its installation. The weighing system accuracy shall meet or exceed that required by the applicable regulations for the installation site.
  4. The weighing system shall be an all-electronic load-cell type. There shall be no mechanical levers, external check rods/stays, or other related parts. The load cells shall send an electronic signal to the system indicator-controller, printer, and related components.
  5. For weighing system installations in the United States (US) and for project-specific designated installations outside the US, the weighing system shall be according to all applicable requirements set forth in the current edition of the NIST Handbook H-44. The system manufacturer shall provide a certificate of conformance according to the National Type Evaluation Program (NTEP) that the weighing system meets the NIST H-44 requirements.

5.2  Foundation and Pit

There is technical requirements for Foundation and Pit for Electronic Truck Weighing System, when assigning vendor for project.

  1. The system supplier shall furnish detailed construction drawings of a recommended foundation and pit design for a nominal 1 kg/cm2 (2000 lbs/ft2) soil-bearing condition.
  2. Unless prohibited by national, provincial, or local authorities and regulations, or required otherwise by the project-specific documents, a “shallow pit” design shall be used. The pit depth shall be sufficient to contain the weighbridge depth plus a nominal clearance below the bottom of it.
  3. The foundation design shall not include a side access to the pit unless the regulations applicable at the installation location require that a deep pit be used.
  4. The foundation design shall include the location of all recommended pit drains and grounding rods for lightning and voltage surge suppression.
  5. The labor, materials, and equipment needed to install the foundation will be provided by others unless specifically required by the project-specific documents.
  6. The system supplier shall provide any special inserts, embedments, mounting brackets, or other items not readily available commercially that are required for the system installation and which must be placed in the foundation/pit forms during pouring of the concrete. These items must be furnished as required to meet Company’ foundation construction schedule.

5.3      Weighbridge

  1. The weighbridge shall consist of prefabricated modules connected together to function as a single assembly. The overall length of the weighbridge shall be as required in the project-specific documents.
  2. The minimum width of the weighbridge shall be 3 m (10 ft).
  3. If constructed of steel, the weighbridge shall be fabricated from structural grade carbon steel as identified in the project-specific documents. The steel material spec and shape/dimensions shall meet the appropriate regulations for the installation site.
  4. The weighbridge shall have a flat top design with none of the structure located above the top of the deck surface.
  5. All access to the weighbridge section’s anchors, connecting hardware, and electronic components (that is, load cells and junction boxes) must be from the top of the weighbridge deck. There shall be no need for any personnel to access the area below the weighbridge confined space-entry to do maintenance or replacement of components.
  6. The weighbridge shall have a concentrated load capacity (CLC) of at least 24,950 kg (55,000 lb). It shall also have a dual tandem axle capacity (DTA) of at least 24,950 kg (55,000 lb). The weighbridge design shall be such that it can accommodate at least 100 trucks per day with a minimum dual tandem axle load of 15,875 kg (35,000 lb) for a period of at least 20 years without fatigue failure.
  7. If the weighbridge sections are “cast-in-place” concrete design, all reinforcement materials and anchors shall be installed in the sections at the factory. No additional forming, bracing, or welding shall be required at the installation site before pouring the concrete.

5.4      Load Cells

  • All load cells shall meet or exceed the minimum standards for weighing accuracy, repeatability, tolerances, and related parameters defined and required by the local regulations for the weighing system installation site. For installations covered by regulations of the US, the applicable regulation shall be NIST Handbook H-44 for class IIIL devices. The load cells shall have NTEP certification.
  • Each load cell shall have a minimum capacity of 22,700 kg (50,000 lb) load with a 200% overload safety factor.
  • The ambient temperature and pressure range capability of the load cells shall be suitable for the ambient conditions at the installation site as given in the project-specific documents.
  • The load cell strain gauge measuring area and any associated electronics shall be enclosed, potted, and/or sealed to exclude moisture, conductive dusts, and corrosive materials. The area shall also be protected from physical damage.
  • Any connections used to join load cell wiring and interface cabling shall be of the waterproof type including elastomeric boots to exclude moisture and debris.
  • Interface signal cable wiring used between load cells and junction boxes shall be protected from damage using stainless steel sheathed cable and/or locating it in conduit. The cabling/conduit shall be securely attached to the weighbridge structure. Loose/dangling/unprotected wiring shall not be allowed.
  • All interface cable junction boxes shall be constructed of stainless steel and be rated weathertight according to NEMA 4X or equivalent. Appropriate cable end connectors and junction box entry fittings shall be used.

5.5      Installation Hardware

    • All baseplates, coverplates, stands, linkages, shims, anchor bolts, hardware, and related items required for the weighbridge and load cell installation shall be furnished by the weighing system supplier.
    • Any special tools, measurement gauges, and related items needed for the weighbridge and load cell installation shall be provided by the weighing system supplier. Any of these items that will be needed for continuing maintenance and repair of the weighbridge and load cells shall remain at the installation site for use as necessary by Company. Items not needed for continuing maintenance and repair may be retained by the weighing system supplier after the installation is complete.
    • Fasteners, shims, and related items used for access and adjustments to various weighbridge and load cell components shall be made from corrosion-resistant materials such as stainless steel.

5.6  Weight Indicator-Controller

  1. The weight indicator-controller, also known as the scale instrument or data terminal, shall be the primary component used to control the operation of the weighing system (that is, load cells and peripheral equipment). It shall provide indication of the weight on the weighbridge, store data, and output information to the ticket printer and other peripheral equipment.
  2. The unit shall be according to all regulations for instrument-controllers applicable at the installation site. For US and designated installation sites, the instrument-controller shall be according to all applicable requirements of NIST Handbook H-44 and be NTEP certified.
  3. The instrument-controller shall be capable of being desktop mounted or panel mounted.
  4. The instrument-controller shall have a corrosion-resistant enclosure that meets one of the following:  NEMA 4X, NEMA 12, or an IEC equivalent.
  5. The instrument-controller shall be capable of operating from an electric power supply of either 115 VAC-1 phase-60 Hz or 220 VAC-1 phase-50 Hz as defined by the project-specific documents. A separate transformer/power converter may be supplied with the indicator- controller to meet this requirement.
  6. The instrument-controller shall have all programming, calibration, and weighing operation done from the face of the unit. The unit shall have battery backup to retain programming and memory in case of electric power supply failure.
  7. The instrument-controller shall be capable of being programmed, calibrated, and displayed in “kilogram” or “pound” units.
  8. The instrument-controller display shall have at least six digits with a minimum digit height of 13 mm (0.5 in).
  9. The instrument-controller shall be capable of storing and outputting the following data as a minimum:
    • Gross weight
    • Tare weight
    • Net weight
    • Date of weight transaction
    • Time of weight transaction
    • Transaction identification number
  10. The instrument-controller shall do self-diagnostics of itself and the weighing system components (for example, load cells). It shall provide indication of any failures or malfunctions found in the system.
  11. The instrument-controller shall be designed to provide protection to the circuitry from radio frequency interference (RFI), electromagnetic interference (EMI), and electrostatic discharge (ESD).
  12. The instrument-controller shall monitor the “zero” weight indication of the weighbridge for any changes resulting from material buildup on it. The indicator-controller shall automatically compensate for any material buildup up to 2% of the weighbridge capacity.
  13. The instrument-controller shall have a standard communication port configured as a bidirectional serial RS232 port for use with the weight ticket printer.

5.7   Weight Ticket Printer

  1. The printer shall be suitable for printing multiple or single copy weight tickets.
  2. The unit shall be according to all printer regulations that are applicable at the installation site. For US and designated installation sites, the printer shall be according to all applicable requirements of NIST Handbook H-44.
  3. The printer shall be suitable for desktop mounting.
  4. The printer shall have an enclosure suitable for use in a weather-protected, temperature-controlled, indoor installation.
  5. The printer shall be capable of operating from an electric power supply of either 115 VAC-1 phase-60 Hz or 220 VAC-1 phase-50 Hz, as defined in the project-specific documents. A separate transformer/power converter may be supplied with the printer to meet this requirement.
  6. The printer shall be capable of printing all information sent to it from the indicator-controller with the following as a minimum:
    • Gross weight
    • Tare weight
    • Net weight
    • Date of weight transaction
    • Time of weight transaction
    • Transaction identification number
    • Truck driver ID
    • Truck detail information
  7. The printer shall have a readily accessible and easily replaceable printing ink source. Preferably, the ink shall be in a “snap-in” cartridge.
  8. The printer’s operation and output shall not be affected by RFI, EMI, and ESD.
  9. The printer shall communicate with the indicator-controller via a bidirectional serial RS232 port.

5.8   Electronic Cables

  • The electronic cable used to connect the weighbridge main junction box to the weight indicator-controller shall be provided by the system supplier.
    • The cable shall have an appropriate quantity and gauge of conductors (as determined by the manufacturer) for the duty.
    • An estimate of the minimum length of cable needed will be provided in the project-specific documents. Some additional length shall be available if needed. The system supplier shall provide the cable as a continuous, one-piece, unspliced, length of cable of proper grade and insulation.
    • The cable shall be stainless steel sheathed for environmental and rodent resistance.
    • If end connectors are required for the cable, they shall be furnished by the system supplier. If strain relief fittings or enclosure (junction box) cable-entry fittings are required, they shall be provided by the system supplier.
    • The cable will be installed by others unless the project-specific documents require otherwise.
  • Any interconnecting cables required between the weight indicator-controller and the printer, and between any other peripheral equipment shall be provided by the system supplier.
    • The cables shall be of appropriate quantity, quality, length, and covering.
    • The cables shall be complete with all end connectors necessary to mate with the devices they are connecting together.
    • The cables will be installed by others unless the project-specific documents require otherwise.

5.9  Surge Voltage and Lightning Protection Equipment

  1. A comprehensive surge voltage and lightning protection system shall be provided for the weighing system.
  2. The protection system shall protect all electronics-containing components and cables of the weighing system from transient overvoltages resulting from power company surges, nearby lightning strikes, and other similar damaging events. This shall include EMI, RFI, and ESD.
  3. The protection equipment shall include at least the following:
    • Electric power supply surge protector(s) for all components using an AC power source.
    • Load cell and junction box protection.
    • Grounding system including ground rod(s), high current conductors, and connecting hardware.
    • Complete installation drawings and details with instruction manuals describing the proper installation, use, and maintenance of the protection system equipment.

5.10  Installation Site Supervision

  1. The system supplier shall provide a knowledgeable person to inspect and supervise the weighing system installation at the plant site. The person shall supervise and take responsibility that the installation of the system is done correctly according to the manufacturers’ drawings, requirements, and recommendations. The labor and related equipment for the installation work will be provided by others unless otherwise specified in the project-specific documents.
  2. The supervisor shall check the foundation construction (done by others) for dimensional arrangement, straightness of walls, locations of any load cells supports, locations of drains for the pit, and any other parameters important to the weighing system’s accurate and reliable operation.
  3. The supervisor shall provide all necessary instruction and supervision for the installation of the weighbridge in the foundation pit including installation of the load cells.
  4. For weighbridges with concrete decks, the supervisor shall provide any instructions and supervision needed for placement of the concrete in the weighbridge sections.
  5. The supervisor shall ensure that all load cell interconnecting cables are installed and connected correctly. The supervisor shall also ensure that the main cable from the weighbridge to the indicator-controller, as well as any other cables between electronic components, plus the connection to the AC electric power supply are done correctly.
  6. The installation of the weighbridge is likely to be in an area where other construction activity is in progress. The supervisor shall conduct the weighing system work in a manner that will not interfere with surrounding construction work being performed by others. The supervisor shall ensure that all necessary steps are taken to preserve and protect weighing system components as well as other materials and work from damage.

5.11  Testing-Calibration-Certification

  1. The system supplier shall be responsible for the testing and calibration of the weighing system after its initial installation.
  2. The system supplier shall provide all test weights needed for the testing and calibration of the weighing system.
  3. The system supplier shall obtain all necessary and applicable site-installation regulatory approvals that are required to make the weighing system “legal for trade.” This shall include all certifications and seals needed from the appropriate “Bureau of Weights and Measures.”
  4. The system supplier shall retest the weighing system within six months after the initial calibration-certification and acceptance by Company if any question arises concerning the weighing system’s accuracy. This retesting shall be done at no additional cost to Company, including any recalibration and recertification found necessary by the retesting.
  5. The system supplier shall provide a test and calibration procedure that shall be followed during the initial setup and commissioning of the weighing system. This shall be part of the documentation submitted.
    • This procedure shall include at least the following information:
      • Acceptable method(s) to be used
      • Amount of calibration weights required
      • Placement (location) of weights on the weighbridge
      • Any precautions to watch for during the testing and calibration
    • The procedure shall include at least one weight test point that is close (+10%) to the maximum expected weight of the heaviest truck that is expected to use the weighing system during operation. For installations in the US, this would be 36,300 kg (80,000 lb). For installations outside of the US, the expected weight of the heaviest truck will be specified in the project-specific documents.
    • One other weight test point at about one-half the maximum expected weight shall be taken to verify the linearity of the installed operating system.
    • Completion of the testing and calibration procedure shall result in a weighing system that is at least accurate to within +0.1% of the applied load plus one-half the amount of the smallest indicated division on the indicator-controller. If local regulations require a closer weighing system accuracy, the weighing system must meet those requirements as well.

6. REQUIREMENTS FOR WEIGHING SYSTEM OPTIONAL COMPONENTS AND INSTALLATION

7. PAINTING

  1. All carbon steel components in the weighbridge shall have surfaces prepared for painting and then painted with a three-coat corrosion-resistant paint system as specified in Table 4, and finish color shall be in accordance with Section (Finish Colors for Painting Piping, Equipment, and Structures) of  Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F). Stainless steel, aluminum, and other nonrusting materials components do not need to be painted. Mass-produced parts (for example, the indicator-controller) may have the manufacturer’s standard paint system.
  2. The corrosion-resistant paint system used on the weighbridge shall be at least as resistant to corrosion as the following system.
    • Grease, oil, and related materials removed by cleaning to meet referenced solvent cleaning standards.
    • Rust, scale, and other residue removed by blast cleaning to meet referenced commercial blast cleaning standards or better.
    • Cleaned surfaces shall be painted with a prime, intermediate, and top coat according to the referenced standards. Color according to the system supplier.
  3. Painting workmanship and quality shall be according to the requirements of Painting and Corrosion Protection of New Construction for Design Temperatures as identified in the project-specific documents.

8.  INSPECTION REQUIREMENTS

  1. Company’ authorized representative shall have the right to inspect all work during progress and after completion to ensure compliance with the specifications’ requirements including proper workmanship, dimensions, scope of supply, and painting. Company inspection requirements will be detailed in the project-specific documents or in the Inspection Requirements Form that accompanies the Request for Quotation and Purchase Order.
  2. The system supplier shall notify Company at least five working days in advance of the required inspection visit milestone dates. The notifications shall be made through the Company expediting group according to the source inspection information provided in the Request for Quotation and Purchase Order.
  3. An “as built” drawing is required as part of the inspection requirements for the weighing systems for Company in America. Refer to the “DOCUMENTATION REQUIREMENTS” section of this specification for details on the “as built” drawing.

9. PREPARATION FOR SHIPMENT

  1.  The weighing system components shall be packaged to prevent damage during shipment.
    • Heavy, relatively damage- and weather-resistant items, such as the weighbridge modules, shall be palletized, skidded, crated, or otherwise packaged to prevent distortion of their structure and damage to their paint.
    • Loose hardware, such as bolts, nuts, washers, and brackets shall be boxed or bagged so that individual pieces are not easily lost.
    • Relatively delicate, fragile, or impact-sensitive components shall be given special attention to prevent any damage. These items shall be placed in plastic bags to seal out water and dirt, and then boxed with shock-absorbing materials to prevent damage. Appropriate warning labels shall be affixed on the outside of the boxes.
  2.  Any components provided by the system supplier that must be installed in the weighbridge foundation during the forming or pouring of concrete (for example, anchors, bulkheads, and plates) shall be identified to Company by the system supplier during the design phase. These components shall be consolidated for early shipment to the installation site at a date that corresponds with the foundation installation schedule.
  3. None of the weighing system components shall be shipped until a “Release Notification” has been issued and Company’ Purchasing Department has been contacted to obtain specific shipping instructions.

10. SPARE PARTS AND SERVICE

  1. The system supplier shall provide a recommended spare parts list for the system as described in the “DOCUMENTATION REQUIREMENTS” section.
  2. The system supplier shall provide full details of his ability to provide a full range of spare parts for the weighing system at short notice.
  3. The system supplier shall provide complete information regarding the service agents available in the location where the weighing system will be installed. The information shall include, as a minimum, contact person names, telephone numbers, notification requirements, response time, and experience.
  4. The system supplier shall provide information on maintenance contracts that it has available for the weighing system, including option information and pricing.

11. DOCUMENTATION REQUIREMENTS

12. BID PROPOSAL INFORMATION

 

 

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