Section 10: Material Weight Verification
Anchor: #i1005652Background
The department should confirm that the material weights used for department purchases are accurate. For all materials delivered to maintenance projects and for use by maintenance personnel, each district must develop and implement a program which will ensure that the weights of materials received are correct when weight is the basis of payment. The weight verification program will include a combination of procedures such as random-check weighing procedures, inspection of scales, the use of portable scales for random weight checks and the observing of weighing at the plant. The district, based on available resources and existing conditions, will determine the selection of the method or methods for verifying weights.
The procedures developed under this program should be used in conjunction with the requirements of Standard Specification Item 6.7, Hauling of Divisible Materials Paid for by Mass or Truck Measure, and any other applicable special provisions or other requirements concerning delivery of roadway materials contained in the bid proposal.
Anchor: #i1005667Notification to Suppliers of Verification Requirements
To ensure that the material shipments are documented by weight tickets from calibrated or certified scales, Clause 44 A of the Open Market Standard Clauses prepared by the General Services Division (GSD) should be placed on all proposals to bid.
To ensure that the suppliers are aware of the random sampling of weight for materials shipped on trucks, Clause 77 A of the Open Market Standard Clauses should be placed on all proposals to bid.
To ensure that the suppliers are aware of the random sampling of weight for materials shipped by the railroad, Clause 78 A of the Open Market Standard Clauses should be placed on all proposals to bid.
NOTE: The standard clauses may be found at http://crossroads/org/gsd/pdf/stdcls.pdf.
Anchor: #i1005692Payment to Suppliers for Expenses Related to Verification
Payment for Rerouting: Payment for rerouted miles for the reweighing procedure must be shown as a separate item on the invoice/billing statement. The number of additional miles, the date of the rerouting and the number of loads must be detailed on the invoice/billing statement.
Payment for Additional Weighing: Purchase orders for road materials do not include payments for additional weighings. The additional weighing must be purchased as a service as outlined in the Purchasing Manual prepared by GSD. All payments for scale-weighing charges will be paid initially by the department to the company that does the weighing. In those cases where an infraction exists, the scale-weighing charge must be deducted from the firm's invoice/billing statement for the material. If the rerouted mileage charge is shown on the invoice/billing statement, it must also be deducted. All deductions must be fully explained on the invoice/billing statement. Payment of materials received will be based on the new corrected weight ticket. A copy of the new corrected weight ticket must be returned to the vendor along with the warrant.
Anchor: #i1005708Verifying Weights
The weight verification program should be uniform throughout the state. In order to accomplish this, the following guidelines are suggested:
Certification of Scales: Whenever possible, a qualified employee of the department should observe the plant weighing operations, check the scales and insure that the scales have either a current certification by the Department of Agriculture or a report of calibration by an approved commercial scale company. The Department of Agriculture generally certifies commercial public scales once a year. When material is purchased and weighed out-of-state, the weighing should be done on scales certified by that state's certifying agency or a commercial scale company. In lieu of the certification by the Department of Agriculture or out-of-state certifying agency, the supplier may furnish a report of calibration from a commercial scale company approved by the Texas Department of Transportation. This report must certify that the scales meet the requirements of the item "Weighing and Measuring Equipment" of the Standard Specifications for Construction of Highways, Streets and Bridges Rev. 93. The supplier should also provide this type of report after the repair of malfunctioning scales. Either a report of calibration or certification will be required on all scales.
Checking Weights—100% Sample: If only a few loads of material are being obtained from a supplier or if the supplier is located nearby, the weights may be verified by observing the weighing of all loads.
Checking Weights—Random Selection: Check weights by random selection whenever possible.
Anchor: #i1005734Shipments by Motor Vehicle
The procedures for checking vehicle weights by random selection of the loads should provide that the loads are checked as near to the delivery point as possible. The rerouting of delivery vehicles should be kept to a minimum. A 5 percent sampling per supplier is suggested. However, in those cases where the amount of material to be delivered is very small (i.e., 75 tons or less) sampling may be waived at the district engineer's discretion. The requirement for certified weights should suffice. A random selection of these very small-quantity suppliers would be checked in this instance.
In any case, the state should reserve the right to reweigh every load. To ensure the validity of this procedure, the supplier and those indirectly involved in furnishing the material should not be informed before delivery which shipment is to be check weighed. The check weighing can be either on commercial scales or on portable scales but must be observed by a department employee.
The following guidelines apply to the use of commercial scales:
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If... |
then... |
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the observed net weight is within 1000 pounds of the supplier's weight |
the net load shown on the supplier's weight ticket is acceptable. |
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the random sample is not within plus or minus 1000 pounds of the net load shown on the supplier's weight ticket |
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a trend of significantly erroneous weight develops (even if the tolerance is never exceeded) |
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In lieu of reweighing on commercial scales, portable scales may be used. Portable scales may be especially useful when a certified commercial scale is not readily available to do the reweighing. The following guidelines apply to the use of portable scales:
- Calibration of portable scales must be kept current.
- Since portable scales cannot be certified by the Department of Agriculture for this type of weighing operations, the observed weights should be used only as a check and not for payment.
- If a trend of erroneous weights develops, the shipments should be rerouted to commercial scales. Concurrently, arrangements should be made with the supplier to recheck his scales and weighing procedures. All material shipments should be discontinued until the problem is corrected.
Shipments by Rail
Random selection of rail shipments also is to be done whenever resources and existing conditions permit. A suggested frequency for reweighing in districts that often receive rail shipments is three shipment checks each year.
If reweighing on a local rail scale is feasible, all cars of the shipment would be reweighed under the following guidelines:
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If… |
then… |
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the total of the checked set of gross weights is within 0.8% of the total of the supplier's net weights for the reweighed rail cars |
the net loads shown on the supplier's weight tickets are acceptable. |
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the total of the checked set of gross weights is not within 0.8% of the total of the supplier's net weights for the reweighed rail cars |
issue new tickets showing corrected weights for payment. |
If reweighing on a local rail scale is not feasible, a minimum of four rail cars would be selected and meticulously unloaded into tarred vehicles for weighing. The commercial vehicle scales should satisfy the same calibration requirements as required of the supplier's scales. Use the following guidelines for reweighing rail shipments on commercial vehicle scales:
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If… |
then… |
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if the total of all vehicle scale net weights is within 1.0% of the total of the supplier's net weights for the reweighed rail cars |
the net loads shown on the supplier's weight tickets are acceptable |
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if the total of all vehicle scale net weights is not within 1.0% of the total of the supplier's net weights for the reweighed rail cars |
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NOTE: In lieu of this correction, the supplier may agree to have all rail cars reweighed at another rail scale installation whose weights would then be used for payment.
If a trend of erroneous weights develops, arrangements should be made with the supplier to recheck his scale and weighing procedures. The effects of moisture differences at times of weighing and possible tare weight errors should also be considered and investigated. Use of the questioned scale should be discontinued until the problem is corrected.
Anchor: #i1005804Record Keeping
A record-keeping system must be developed and kept current showing random sampling activities and results, overloads, plant inspections, weighing procedure observations and other relevent information. A copy of the supplier's plant certification or calibration will be retained in this file.