ASTM F3427-25

1.1 When conducting test methods, it is important to consider the role that the environmental conditions play in measurement of exoskeleton safety and performance. Exoskeletons are designed to be operated both indoors and outdoors under conditions specified by the manufacturer. Likewise, end users of the exoskeletons will be using these exoskeletons in a variety of environmental conditions.

When conducting and replicating ASTM Committee F48 test methods by exoskeleton manufacturers and users, it is important to specify and document the environmental conditions under which the exoskeleton is to be tested as there will be variations in system performance caused by the conditions, especially when comparing and replicating sets of test results. It is also important to consider changes in environmental conditions during the course of operations (for example, transitions between conditions).

As such, environmental conditions specified in this practice are static, dynamic, or transitional, or combinations thereof; with the exoskeleton stationary or in motion. This practice provides brief introduction to the following list of environmental conditions that can affect performance of the exoskeleton and the exoskeleton user:

• 1.1.1 Floor or ground surface;
• 1.1.2 Temperature;
• 1.1.3 Humidity;
• 1.1.4 Atmospheric pressure;
• 1.1.5 Lighting;
• 1.1.6 Air flow and quality;
• 1.1.7 External sensor emission;
• 1.1.8 Proximity to potential hazards;
• 1.1.9 Electrical interference;
• 1.1.10 Vibrations;
• 1.1.11 Contaminants;
• 1.1.12 Boundaries;
• 1.1.13 Additional categories, for example underwater, extraterrestrial, may also be added to this standard as the exoskeleton industry applications evolve in these areas.
• 1.1.14 This practice then breaks down each condition into sub-categories so that the user can document the various aspects associated with the category prior to exoskeleton tests defined in ASTM Committee F48 test methods listed in Section 2. It is recommended that salient environment conditions be documented when conducting ASTM Committee F48 test methods.

1.2 The environmental conditions listed in 1.1 to be documented for exoskeleton(s) being tested are described and parameterized in Section 4 and allow a basis for performance comparison in test methods. The approach is to divide the list of environmental conditions into sub-conditions that represent the various aspects of the major category (for example, type-concrete within floor and ground surface). Where necessary, this practice also provides guidelines (for example, grade levels and particulates) to document environmental conditions in an existing environment.

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

4.1 This section provides a description of the environmental conditions listed in Section 1 and describes the sub-conditions within each condition. Examples provided for many of the conditions and sub-conditions are provided as guidance only. Each of the conditions described should be evaluated and documented as set forth in Sections 5 – 7.

4.2 Environment Consistency: Static, Dynamic, Transitional 

4.2.1 Static is when the environment is similar throughout the test apparatus. For example, there are minor fluctuations in temperature throughout the apparatus as shown in Fig. 1 and Fig. 2. Dynamic is when the environment significantly differs within the test apparatus. For example, when the temperature changes between repetitions as shown in Fig. 3. Transitional is when the environment significantly differs in different areas within the test apparatus as shown in Fig. 4. The intent here is to not give specific guidance, but to provide a high-level classification of a particular set of environmental conditions. If environment consistency is dynamic or transitional, or both, a report form (see Section 7) for each unique set of environmental conditions should be completed.

4.7.5 Lighting Levels: 

• 4.7.5.1 Level 1—0 lx to 1 lx (for example, dark);
• 4.7.5.2 Level 2—2 lx to 99 lx (for example, dim);
• 4.7.5.3 Level 3—100 lx to 1000 lx (for example, office environment);
• 4.7.5.4 Level 4—1001 lx to 9 999 lx (for example, high intensity work light, spotlight);
• 4.7.5.5 Level 5—10 000 lx and above (for example, full sunlight).

4.7.6 Spectrum—Identify primary color and peak wavelength.

4.7.7 Polarization—Identify the polarizing source and angle with respect to a known reference (for example, world coordinates).

4.7.8 If more specificity of measurement is required, the following documents and standards may be used:

• 4.7.8.1 “Recommended Light Levels” by National Optical Astronomy Observatory⁹, which includes common/recommended indoor/outdoor light levels;
• 4.7.8.2 British Standard, BS 667:2005;
• 4.7.8.3 ISO 15469:2004, which defines a set of outdoor daylight conditions linking sunlight and skylight for theoretical and practical purposes; and
• 4.7.8.4 The Lighting Handbook.¹⁰

4.8 Air Flow and Quality: 

4.8.1 Air flow and quality refers to the ability that an exoskeleton or exoskeleton-user, or both, is affected by air particulates or wind, or both, or that onboard exoskeleton sensor(s) are affected by the presence of precipitation or air particulates, or both. Air quality can also affect exoskeleton performance, for example heat transfer characteristics. Air quality may affect the exoskeleton performance in terms of joint motion or electronics and automatic exoskeleton functionality, or both. Air quality depends upon the size and volumetric density of particulates in the air. For relative comparison, the average human eye cannot see particles smaller than 40 µm, fog from water vapor typically includes particle sizes from 5 µm to 50 µm, and dust particles are typically 0.1 µm to 100 µm. An ISO Class 1 cleanroom has no more than 10 particles larger than 0.1 µm in a cubic meter of air. Fog (water vapor) particle density of 1 amg allows human visibility of about 125 m at ground level.

4.8.2 Air Velocity and Direction—Document air flow source location and elevation with respect to the exoskeleton (refer to Fig. 6).

4.8.3 Air Particle Density—Optionally, measure the air particle size and volumetric density:

• 4.8.3.1 Clear (for example, clean room, no visible air particulates);
• 4.8.3.2 Moderate (for example, visible fog, dust, light to moderate rain/snow/fog);
• 4.8.3.3 Dense (for example, dust storm, heavy snow/rain/fog).

4.8.4 If more specificity of measurement is required, the following standards may be used:

• 4.8.4.1 ISO 14644-1:2015 for air particle density (clear), and
• 4.8.4.2 ANSI/IEC 60529-2004.

4.9 External Sensor Emission: 

4.9.1 External emitters are outside of the exoskeleton (for example, from a nearby equipment source) and can potentially interfere with the exoskeleton sensor or control system. External radiation sources can affect the exoskeleton performance, for example: lasers, ultrasonics.

4.9.2 External Emitter Configuration: 

• 4.9.2.1 Type of emitter(s);
• 4.9.2.2 Quantity of emitter(s).

4.9.3 External Emitter Source Location—Document emitter source location and elevation with respect to the vehicle (refer to Fig. 6):

• 4.9.3.1 Elevation with respect to exoskeleton or exoskeleton path;
• 4.9.3.2 Location with respect to the exoskeleton or exoskeleton path.

4.9.4 Spectrum—Identify primary color and peak wavelength.

4.9.5 Electrical shock or arc flash, or both.

4.9.6 Sound: 

• 4.9.6.1 Source (for example, gun, CNC machine),
• 4.9.6.2 Type (for example, gunshot, machinery),
• 4.9.6.3 Duration/Frequency (for example, steady, intermittent, percussive),
• 4.9.6.4 Intensity (for example, soft, loud), and
• 4.9.6.5 Pitch (for example, high, low Hz).

4.10 Proximity to Potential Hazards: 

4.10.1 Moving mechanical systems.

4.11 Electrical Interference: 

4.11.1 Some surfaces are not conductive enough to provide adequate grounding for an exoskeleton. Exoskeletons have a floating ground. As static builds up on the exoskeleton and the voltage drop from the positive lead of the battery and the chassis