Downloaded from https://www.everyspec.com TOP 1-2-621 6 February 2009 1. SCOPE. a. This TOP provides guidance procedures to conduct sand and dust tests on military materiel using an outdoor test facility. Outdoor facilities are required when a chamber test is not feasible due to chamber size limitations. Two procedures are described. One approximates the sand test guidance outlined in Military Standard (MIL-STD)-810G 1 . The second method is offered as an alternative and attempts to meet both sand and dust test requirements in one test; i.e., sand and dust are mixed at concentrations approximating MIL-STD-810 test levels.
This document describes the instrumentation, test equipment, and data collection and processing procedures. b. Limitations. (1) Temperature. MIL-STD-810 sand/dust procedures require the unit under test (UUT) to be tested at the high operating or storage temperature (~ 60 - 71˚C). Most Army test chambers are limited in size and thus sand/dust testing of large test items may not be possible. This TOP provides an alternative test method which recommends testing at ambient temperature conditions. (2) Weather. Weather conditions need to be monitored as temperature, relative humidity, and ambient wind conditions affect test equipment performance.
This TOP describes test methods that are performed outdoors under the prevailing weather conditions and thus testing is limited to calm, dry days [recommend winds less than 4.5 m/s (10 mph) with occasional gusts up to 7 m/s (15 mph) and relative humidity (RH) less than 30%]. (3) Particle Size and Granularity. This method recommends utilizing sand material that is supplied by local businesses (playground sand). This sand material must be characterized before test conduct to determine if the product meets the customer’s objective (i.e., sand particle size distribution in the UUT’s anticipated deployment location).
Use sand of sub-angular structure, a mean Krumbein number range of 0.5 to 0.7 for both roundness and sphericity and a hardness factor of 7 mohs (see Appendix B). The media may be tailored by adding “designer” dust but the result may not exactly match the particle size and granularity requirements of MIL-STD-810. (4) Dust Concentration. The dust concentration values in the combined sand/dust method of this TOP may be lower than the MIL-STD-810 requirement of 3 to 17 g/m 3 . Test equipment limitations, test item size, and outdoor weather conditions may significantly alter the amount of material impacting the UUT. (5) Wind Speed.
MIL-STD-810 specifies a wind speed of 18 m/s (40 mph) for sand and 9 m/s (20 mph) for dust testing. The combined sand/dust test described in this method is conducted at 18 m/s (40 mph); therefore, test results may differ from those observed in the conventional chamber test. Wind gusts or higher speeds may be added if required by the life cycle environmental profile. The MIL-STD-810 dust procedure is performed to ascertain the ability of equipment to resist the effects of dust particles which may penetrate into cracks, crevices, and joints (e.g., the caking of dust at openings).
Combining the blowing dust with * Superscript numbers and letters correspond to those found in Appendix C, References. 2