Booster Margins of Safety

(Updated 26 February 2013)

Reference

A GENERAL STRUCTURAL CRITERIA USED IN SYSTEMS RESEARCH AND PLANNING DIVISION STUDIES OF NONRECOVERABLE BOOST VEHICLES by J.R. Henry (8 April 1963) (Link to DTIC)

Definitions:

LIMIT LOAD is the maximum anticipated load, or combination of loads, which a structure may be expected to experience during the performance of specified missions in specified environments.

ULTIMATE LOAD Is obtained by multiplying the limit load by the ultimate factor of safety.

PROOF PRESSURE is that pressure which is applied to a pressure vessel as a test at room temperature as evidence of satisfactory workmanship and material quality. Proof pressure is derived by multiplying limit pressure by the proof pressure factor.

Flight Loads


Limit

Ultimate

Manned Payloads

1.00

1.40

Unmanned Payloads

1.00

1.25

Non-Flight Loads (Other than Pressure)


Limit

Ultimate

Dangerous to Personnel

1.00

1.50

Remote to Personnel

1.00

1.25

Pressure Loads

MAIN LIQUID PROPELLANT TANKS


Limit

Proof

Ultimate

Burst

Manned Payloads

1.00

*

1.50

1.40

Unmanned Payloads

1.00

*

1.25

1.25

SOLID ROCKET MOTOR CASES


Limit

Proof

Ultimate

Burst

Manned Payloads

1.00

*

1.25

1.25

Unmanned Payloads

1.00

*

1.15

1.15

MISCELLANEOUS


Limit

Proof

Ultimate

Burst

Liquid propellant thrust chambers and liquid/solid rocket nozzles

1.00

*

1.25

1.25

Pneumatic Vessels (incl. accumulators and pressurization bottles)

1.00

1.67

--

2.22

Hydraulic Vessels (Incl. accumulators and pressurization bottles)

1.00

2

--

4.00

Hydraulic Vessels Normally Under Oil Pressure Only

1.00

1.5

--

2.00

Hydraulic and Pneumatic Lines, Fittings and Hoses

1.00

2

--

4.00

Main Propellant Supply and Vent components

1.00

1.5

1.88

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