521.4Method 521.4 method

MIL-STD-810H, Environmental Engineering Considerations and Laboratory Tests

Last Updated 29 Oct 2026

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521.4 ICING/FREEZING RAIN CONTENTS

Paragraph		Page
1.	SCOPE	1
1.1	PURPOSE	1
1.2	APPLICATION	1
1.3	LIMITATIONS	1
2.	TAILORING GUIDANCE	1
2.1	SELECTING THE ICING/FREEZING RAIN METHOD	1
2.1.1	EFFECTS OF ICING/FREEZING RAIN	1
2.1.2	SEQUENCE AMONG OTHER METHODS	2
2.2	SELECTING PROCEDURE VARIATIONS	2
2.2.1	ICE FORMATION	2
2.2.1.1	PRINCIPAL CAUSES	2
2.2.1.2	TYPES OF ICE	2
2.2.2	CONFIGURATION AND ORIENTATION	3
2.2.3	TEST TEMPERATURE	3
2.2.4	WATER DELIVERY RATE	3
2.2.5	WATER DELIVERY METHOD	3
2.2.6	DROPLET SIZE	3
2.2.7	ICE THICKNESS	3
2.3	OPERATIONAL CONSIDERATIONS	3
3.	INFORMATION REQUIRED	4
3.1	PRETEST	4
3.2	DURING TEST	4
3.3	POST-TEST	4
4.	TEST PROCESS	4
4.1	TEST FACILITY	4
4.2	CONTROLS	4
4.3	TEST INTERRUPTION	5
4.3.1	INTERRUPTION DUE TO CHAMBER MALFUNCTION	5
4.3.2	INTERRUPTION DUE TO TEST ITEM OPERATION FAILURE	5
4.4	TEST SETUP	5
4.5	TEST EXECUTION	5
4.5.1	PREPARATION FOR TEST	5
4.5.1.1	PRELIMINARY STEPS	6
4.5.1.2	PRETEST STANDARD AMBIENT CHECKOUT	6
4.5.2	PROCEDURE-ICE ACCRETION	6
5.	ANALYSIS OF RESULTS	7
6.	REFERENCE/RELATED DOCUMENTS	7
6.1	REFERENCED DOCUMENTS	7
6.2	RELATED DOCUMENTS	7

MIL-STD-810H METHOD 521.4

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MIL-STD-810H

METHOD

521.4 METHOD 521.4

ICING/FREEZING RAIN

NOTE: Tailoring is essential. Select methods, procedures, and parameter levels based on the tailoring process described in Part One, paragraph 4.2.2, and Annex C. Apply the general guidelines for laboratory test methods described in Part One, paragraph 5 of this Standard.