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| SURFACE PYROTECHNICS AND PROJECTORS |
| Chapter 3 - SURVEILLANCE |
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21. This chapter implements the Bureau of Ordnance Manual, which requires periodic data on pyrotechnic performance of all lots in service in order to secure the rate of de-terioration and to identify the causes of any failures. The following excerpts are quoted as essential. |
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From Section 12C12, "Included in the category of explosive ... are, ... fireworks and py-rotechnics, ..." |
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From Section 12C12, "(a) Surveillance (General) as used in these instructions, means close observation, rigid inspection, careful examination, and thorough testing, ... of (py-rotechnics) by the method and in the manner prescribed for each specific material in or-der to determine the suitability of the material for the intended purpose or for its safety for further storage. |
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"Surveillance applies not only to the (pyrotechnic) elements themselves, but also to methods of handling, packing, marking, storing, segregation, and shipping; to condition of containers, and to reports of conditions; and in general all precautions and instructions tending to protect property and personnel against the hazards inherent ..." |
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"(b) Officers to familiarize themselve with the practical methods of exeamination and tests - Officers charged with the care of (pyrotechnics) shall thoroughly familiarize themselves with the practical methods of making such examinations and tests and shall be held responsible for the accuracy thereof and for the correctness of the official re-ports thereon. In order that the test may be of value, ... (in determining the rate of de-terioration and the causes of failures), it is essential that the methods in all details shall be uniform throughout the service, and those charged with this duty must follow strictly the prescribed methods." |
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From 13G5, "Surveillance (Specific) (a) All lots of pyrotechnic ammunition shall be ins-pected at least once a year. The inspection shall include an examination of packing boxes and containers and the opening of one or more containers for examination of indi-vidual rounds, which, if satisfactory, shall be carefully repacked and sealed. |
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(Reports of abnormal conditions shall be rendered to the Bureau of Ordnance.) |
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(b) (This paragraph is implemented by the following text) |
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22. Pyrotechnice Data Cards will be prepared in check-off form and packed in each con-rainer with all new production, so that performance can be checked off by the user and the report forwarded direct to the Bureau. This will eliminate the paperwork now neces-sary for recording, composing, and typing the reports required, and provide more comple-te data. Fig. 1 shows a typical data card. |
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Figure 1. – Typical Data Card (Front and Back) |
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(a) These forms schedule a minimum amount of surveillance firing, preferably contempo-raneous service firing. This minimum is necessarily set with practical considerations of consumption and economy in mind, and accepts a certain degree of inaccuracy in the estimates of quality. Therefore, the more that service firings are reported by users, the more accurately the Bureau can operate in their behalf. Atlhough it is not required that the performance of every round fired by reported, it is expected that users will recognize that check-offs on every round reasonably possible, forwarded to the Bureau, will lead to better pyrotechnic performance in the future. |
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(b) For some time to come, the current stocks, packed without forms, will be in use. For these it will be necessary to use the basic form (NAVORD FORM 1187) according to di-rections given in the "INSTRUCTIONS FORE USE OF PYROTECHNIC AMMUNITION PERFOR-MANCE DATA CARDS," (NAVORD FORM 1187A). Requests for these forms should be sub-mitted on NAVORD FORM 1 to the nearest Ordnance Publications Distribution Center. |
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23. When testing, if one or more duds occur, a label giving particulars (see Fig. 2), should be affixed to each remaining round or container of that lot. This suspect material should be turned in for replacement at the first opportunity. |
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Figure 2. – Label for Suspect Material |
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A. For Suspect Material Returned by Ships: |
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24. Naval Ammunition Depots and Naval Magazines will handle such returns as follows: |
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(a) Inspect each item for label properly filled out and secured to the round or the contai-ner. Verify the lot description marked on the label. |
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(b) Replace, if requried, from an unrestricted lot. |
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(c) Segregate the returned rounds. Restrict the issue of any other rounds of that lot which may be in stock. |
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(d) Notify the Chief of the Bureau of Ordnance, giving full particulars, and requesting dis-position. |
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B. Procedure for Surveillance Firings from Pyrotechnic Lots in Stocks at Naval Am-munition Depots, Magazines, and other Stores Facilities: |
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Lots in stock more than two years beyond the dates of manufacture marked on each round shall be subjected to performance surveillance and reported according to their Per-formance Data Cards, except the number tested shall be guided by the Sequential Test Plan shown by charts. See Fig. 3. |
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Figure 3 – Sequential Test Charts |
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These charts utilize the law of probability, to distinguish between "good" and "bad" lots with the minimum of firing. |
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The two curves in the lower chart show the propability of acceptance and the average sample size respectively for lots of various percentage defective which might be encoun-tered. The test should be guided by plotting on the upper chart as each round is tested, stopping the test as soon as either the rejection or the acceptance line is crossed. |
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The following expression of the chart in tabular form condenses the idea, and may be used as an alternative. |
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NUMBER OF |
NUMBER OF ROUNDS FIRED |
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LOT |
INDETERMINATE |
LOT |
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0 |
--- |
5 or less |
6 or more |
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1 |
--- |
10 or less |
11 or more |
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2 |
--- |
14 or less |
15 or more |
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3 |
6 or less |
7 to 18 |
19 or more |
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4 |
11 or less |
12 to 21 |
22 or more |
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5 |
15 or less |
16 to 24 |
25 or more |
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6 |
25 or less |
--- |
--- |
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25. The Bureau of Ordnance will estimate the actual quality, from all analogous data on the lot, and if data are insufficient, will specify a definitive sequential test to determine final disposition, and will by Ordnance Circular Letters, promulgate lists of lots found de-fective by surveillance. |
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