The Fastener Quality Act (FQA) was enacted after several major fastener failures occurred in the 1980s. The US Congress investigated and found widespread problems throughout the industry. industry related standards, quality control, safety and inspection. In addition, foreign suppliers provided falsified and low-quality certificates.
To protect the public from further failures, the FQA requires: conformity to the specifications to which they are manufactured; the accreditation of laboratories that carry out fastening element testing; and inspection, testing and certification according to standardized methods. It may be common to experience this requirement for DOT work, aerial signals, etc.
The FQA only applies to items such as metal bolts, nuts, screws, studs (0.25 inches / 6 mm or larger), or direct tension hardened (DTI) washers. When a fastener subject to the FQA must be hot-dip galvanized, paragraph 6.4 of ASTM A153 states:
6.4 The sampling method for fasteners that must meet the standards of the Fastener Quality Act is described in Guide F1470. Sample quantities and definitions of terminology are included in the reference specification.
For the galvanizer, the main exception to the law is fasteners manufactured in a facility registered in a recognized quality system, such as ISO 9000. In practice, if your galvanizing plant is ISO certified, you will already be complying with the law and will not need any further measures than galvanizing according to the ASTM A153 standard. Other exceptions to the law are under the control and specification of the owner.
Otherwise, to help your customer remain FQA compliant, you will still hot-dip galvanize to ASTM A153, but instead of using the inspection sampling protocol in paragraph 6 of ASTM A153, you will need to use the sampling procedure described in ASTM F1470, Practice for Sampling Fasteners for Specified Mechanical Properties and Performance Inspection.
The F1470 standard describes two different types of inspection lots: Production Lot Detection Process and Production Lot Prevention Process. Differences in lot types imply different sampling plans, which specify the number of test items to perform various test methods during inspection of the finished product. It is important to ensure that the customer specifies what type of lot is needed.
To determine how many samples are needed to verify compliance with ASTM A153 based on lot type and size, see Table 3 of F1470. According to the F1470 standard, the acceptance number in all cases is zero defects.
| Sample size | ||||
|---|---|---|---|---|
| Lot Size | TO | b | c | d |
| 1 to 2 | 2 | 1 | 1 | Note A |
| 3 to 15 | 3 | 2 | 1 | Note A |
| 16 to 25 | 4 | 3 | 1 | Note A |
| 26 to 50 | 5 | 4 | 1 | Note A |
| 51 to 90 | 6 | 5 | 2 | 1 |
| 91 to 150 | 7 | 6 | 2 | 1 |
| 151 to 280 | 10 | 7 | 2 | 1 |
| 281 to 500 | 11 | 9 | 3 | 2 |
| 501 to 1,200 | 15 | 11 | 3 | 2 |
| 3,201 To 10,000 | 22 | 15 | 4 | 3 |
| 10,001 To 35,000 | 29 | 15 | 4 | 3 |
| 35,001 To 150,000 | 29 | 15 | 5 | 3 |
| 150,001 To 500,000 | 29 | 15 | 6 | 4 |
| 500,001 and over | 29 | 15 | 7 | 5 |
| Note A: Suppliers must provide the results of the certified tests from which the shipping lots come. If certified test reports are not available, the supplier must default to sample size C and perform the required tests. | ||||
F1470 Table 3: Production lot sampling plan
The process type of the production lot will determine which column (A, B, C or D) should be referenced for the sample size of each inspection criterion (coating thickness, visual appearance, adhesion, etc.), as summarized in table F1470 Production Lot Sample Size: Detection Process vs. Prevention. For example, a lot size of 500 items under the screening process requires testing 11 samples for coating thickness, 11 samples for visual appearance, and 3 samples for adhesion (when there is evidence of an adhesion problem).
| Inspection criteria | Production Batch - Detection Process | Production Lot - Prevention Process |
| Layer thickness | See F1470 Table 3 Sample size Column A | See F1470 Table 3 Sample size Column B |
| Visual aspect | See F1470 Table 3 Sample size Column A | See F1470 Table 3 Sample size Column B |
| Accession | See F1470 Table 3 Sample size Column C | See F1470 Table 3 Sample Size Column D |
F1470 Production Lot Sample Size: Detection Process vs. Prevention
