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ASME PALD 4a-1988 — Vehicle Support Stands Safety Standard Addenda (a)
📦 ASME/ANSI PALD-4a-1988 is the first Addenda to the ASME/ANSI PALD-4-1987 Vehicle Support Stands volume. It was approved by ANSI on October 28, 1988, and issued on January 15, 1989. Addenda revise the base edition through replacement pages, with changes marked by the margin note (a); content changed in the formal 1987 revision is marked (87). The emphasis of this Addenda is on the proof load definition, operating control requirements, and inspection provisions, making the safety requirements for vehicle support stands more explicit and verifiable.
💡 Effect of an Addenda: under the PALD series rules, revisions become effective three months after the Addenda issue date. Manufacturers, purchasers, and inspectors working with the 1987 edition should adopt this Addenda in parallel to keep designs and documents compliant with current requirements.
1. Summary of Changes 📌
| Page | Location | Change |
|---|---|---|
| iii | Foreword | Editorially revised in its entirety |
| 1–3 | Introduction | (1) Editorially revised in its entirety; (2) previous changes from the 1987 edition indicated by (87) |
| 5 | Section 2 — definition of “proof load” | Revised |
| 5 | Para. 3.4 operating controls | Revised |
| 9 | Para. 7.1.3(c) | Revised |
⚠️ An Addenda consists of replacement pages only; it is not a standalone standard. When citing PALD-4-1987, the currently effective text is the 1987 base content plus the replacement pages of all published addenda (4a, 4b, 4c). Drawings, manuals, and inspection procedures should state which addenda they follow.
2. Proof Load Definition and Design Requirements 🔬
The “proof load” definition is the key criterion for design qualification testing. This Addenda revises it so that test load determination and acceptance are more explicit: the proof load is a load greater than the rated capacity, applied centrally to the saddle to confirm the integrity of the structure; in the design qualification testing (Section 5), the centered load test and the off-center load test are applied as shown in Figures 3 and 4 of the Standard. In parallel, the revision to para. 3.4 refines the design requirements for operating controls:
- Visibility: controls must be readily visible and accessible to the operator and not obscured by structure.
- Safety: the operator must not be subjected to pinch points, sharp edges, or snagging hazards when operating the controls.
- Clarity: the operation of controls should be clear by position, function, labeling, or a combination thereof.
🚨 The “misuse-resistant design” of operating controls is a point of emphasis in this Addenda: if the locking/unlocking operation can be accidentally triggered or misread, the safety of personnel working beneath the vehicle is directly threatened. Design reviews should specifically check control placement and labeling.
3. Use, Maintenance, and Inspection Essentials 🛠️
The revision to para. 7.1.3(c) strengthens in-service requirements:
- 🔍 Pre-use inspection: before each use, check that the column locking device works reliably and that the locking pin, if used, is in place and secured to the stand.
- 🔧 Center the load: the load must be placed on the center of the saddle; off-center loading multiplies the tipping moment.
- 📐 Use stands in pairs: stands must be used in pairs, on hard, level surfaces, as required by the warning label.
- 📋 Functional damage: any stand showing permanent deformation of the structure, saddle, or column (functional damage) must be removed from service, scrapped, or repaired.
4. Impact on Manufacturers and Users 📊
For this Addenda, manufacturers should update design and test documentation promptly: organize design qualification testing to the revised proof load definition, verify that operating controls meet para. 3.4, and reflect the latest wording on nameplates and warning labels. Users and inspection bodies should update their procedures to incorporate the Addenda into acceptance and periodic inspections, so that “current-version conformity” is documented and traceable.
5. Frequently Asked Questions ❓
❓ Q: How does PALD-4a-1988 relate to the 1987 edition?
A: 4a-1988 is the first Addenda to the 1987 edition. The effective text is the 1987 base pages plus this Addenda’s replacement pages (followed by 4b and 4c); cite the Standard as “including Addenda PALD-4a-1988.”
A: 4a-1988 is the first Addenda to the 1987 edition. The effective text is the 1987 base pages plus this Addenda’s replacement pages (followed by 4b and 4c); cite the Standard as “including Addenda PALD-4a-1988.”
🔍 Q: What is the difference between the margin notes (a) and (87)?
A: (a) marks changes introduced by this Addenda (the first one); (87) marks content changed in the formal 1987 revision. The different markers let users trace each change to its source.
A: (a) marks changes introduced by this Addenda (the first one); (87) marks content changed in the formal 1987 revision. The different markers let users trace each change to its source.
❓ Q: When do the Addenda revisions take effect?
A: Under the PALD series rules, Addenda revisions take effect three months after the Addenda issue date; manufacturers must produce and test to the new requirements thereafter, and users must adopt them in inspection documents.
A: Under the PALD series rules, Addenda revisions take effect three months after the Addenda issue date; manufacturers must produce and test to the new requirements thereafter, and users must adopt them in inspection documents.
❓ Q: Why is an Addenda issued in January 1989 numbered 1988?
A: The year in an Addenda number is the year of approval (ANSI approved it on October 28, 1988); the issue date comes after approval. Numbering by approval year while issuing later is common ANSI practice.
A: The year in an Addenda number is the year of approval (ANSI approved it on October 28, 1988); the issue date comes after approval. Numbering by approval year while issuing later is common ANSI practice.
