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Introduction
Wind tunnel testing inherently involves potential hazards that could affect personnel, equipment, or test progress.
Controlling these hazards is essential to ensuring personnel, equipment, and test operations are protected from harm and that the facilities operate to their fullest capacity. Therefore, model and associated equipment design and operation must incorporate safety principles presented in this document.
The Ames Health and Safety Manual, AHB 1700-1, chapter 5, "Facility Operational Safety" describes procedures used to ensure equipment and systems are designed and operated safely.
The risk associated with conducting a test is a function of the hazard's severity and the likelihood or probability that the hazard will actually be encountered.
The Ames Health and Safety Manual, AHB 1700-1, describes in general terms how the risk of hazards should be identified and mitigated. The FO Division has further refined that process and adapted it to wind tunnel testing and operations as described in the following paragraphs.
The Customer is responsible for preparing the Risk Assessment, following guidelines presented in this document, and presenting the results of the assessment at the Initial Test Planning Meeting.
The Division may request, based on the Risk Assessment, that a Hazards Analysis be performed. This may be done by the customer or by the Division's System Safety Analyst or a combination.
First, hazard severity is assessed, then probability, then these factors are considered together to determine the final risk. Finally, hazard controls are implemented to decrease or control the risk.
There are four hazard-severity categories as described in the following table.
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I Catastrophic |
• Death or permanent debilitating injury |
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II Critical |
• Disfiguring injury or lost time greater than three months |
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III Marginal |
• Lost-time injury greater than one day |
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IV Safe |
• No lost-time injuries |
There are four hazard-probability levels as described in the following table.
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Probable--Likely to occur several times during the life of the system or test period |
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Remote--Likely to occur once during the life of the system or test period |
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Improbable--Not likely to occur during the life of the system or test period |
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Highly improbable--Occurrence is considered to be extremely unlikely during the life of the system or test period |
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These risk severity categories and probabilities must be considered together to determine the final risk evaluation. Different levels of risk require different management approval, as described next.
The matrix below shows who is responsible for authorizing the risk acceptance for each combination of severity and probability. These sign-off authority requirements apply to Test Readiness Reviews (TRRs), Operational Readiness Reviews (ORRs), and Hazard Reports that result from system safety analyses of test installations and facility modifications.
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Probability Level |
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Hazard Category |
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I Catastrophic |
Center Director |
FO Division |
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II Critical |
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III Marginal |
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IV Safe |
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The Ames Health and Safety Manual, AHB 1700-1, describes the order of preference for controlling hazards. The FO Division also implements controls for facility and test hazards following this order of preference, summarized as follows.
1. Design for Minimum Hazards - Provide inherent system safety by selecting appropriate design features and qualified components.2. Incorporate Safety Devices - Includes mechanical barriers or inhibiting mechanisms. Conduct periodic functional checks of such safety devices.
3. Incorporate Protective Systems - Includes fire suppression systems, radiation shielding, flash shields, containment, etc.
4. Incorporate Warning Devices - Includes signals, lights, signs, horns, etc., and include requirements for training to ensure a proper and timely response to warning devices.
5. Institute Special Procedures - Include emergency procedures that effectively limit initiating a hazardous sequence. Includes caution and warning statements in normal operating procedures. A formal Operational Hazards Analysis will be required for all deviations from the Standard Operating Procedure (SOP) Manual for each facility.