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ICS, Doc ID, STANAG Ed 6. Title, CLIMATIC CONDITIONS – AECTP Edition 1. Original Title. Category, TS. Location. AECTP (Edition 1) Leaflet /2 World-wide Ambient Air Temperature and Humidity Conditions and Levels of Direct Solar Radiation Additional Climatic. NATO AECTP CLIMATIC CONDITIONS. Amendment by NATO Publication, 05/01/ This document is an amendment. View the base document.

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Documents Flashcards Grammar checker. Temperatures in Fully Air-conditioned Compartments Temperatures in Partially and Non-conditioned Compartments Effects of Heat on Humidity Humidity in Fully Air-conditioned Compartments Humidity in Partially and Non-conditioned Compartments Altitude above Sea Level Rates of Change of Air Pressure Normal Operational Transient Changes Low Temperature and Dew Point Aircraft Impact 2330 Super-cooled Water Droplets Proximity to Refrigerated Units The purpose of the AECTP series of leaflets is to present characteristics and data samples of natural and induced climatic conditions that influence the design of materiel.

For the purpose of this document, induced climatic zectp are the ambient environmental conditions resulting from the modification of the natural climatic conditions due to the structure in which, or on which, the materiel is utilised.

Leaflet gives general guidance on the types and causes of natural and induced climatic environments, and gives information that is applicable to a variety of materiel types and platforms. Induced environments included are: Sections to cover different situations in which materiel may be found, and follow a standardised format. For each situation, the characteristics of relevant induced environments are described for each set of circumstances that may apply.

The potential damaging effects of those environments are described, and advice is given on the selection of test methods and severities.

aectp climatic conditions

AECTP complements, amplifies, and extends information previously contained in STANAG by identifying potential damaging effects that natural and induced environmental conditions have on materiel, and by providing guidance on the selection of suitable test methods.

AECTP series of leaflets are organised around classes of materiel items. The leaflets focus on the effects of the natural environment, or on the act or process by which environments experienced by materiel items are altered by environmental factors inherent in circumstantial conditions, platforms, or other materiel items that surround them.

These leaflets are not intended to be comprehensive. When used in conjunction with AECTPs and and other sources of relevant informationthese leaflets provide information on climatic conditions that should enable a comprehensive and cost effective set of environmental tests type approval or qualification to be selected, formulated, and conducted in response to project environmental and related requirements.

AECTP does not address all environments arising from accident, hostile conditions or nuclear effects. To permit customers or potential customers to ask intelligent questions to confirm that key environmental characteristics and issues have been, or will be addressed by suppliers or potential suppliers.

To assist project engineers to compile Environmental Requirement or Life Cycle Environmental Profile specifications by identifying all major environments and by illustrating and quantifying key environmental characteristics and parameters that may influence specifications.

To assist project engineers to prepare Environmental Design Specifications by providing improved environmental characteristics data that will help them to select more valid initial design values. To assist design engineers by indicating potential failure modes that specific environmental characteristics could induce, and thereby providing pointers to monitor during design and testing.

To assist test engineers in preparing test specifications by indicating which test methods are preferred when considering how to test for specific climatic environmental effects. To assist test engineers to compile programmes to acquire good quality field data.

This aspect is covered extensively in these leaflets. Such data are used primarily to formulate test levels for qualification trials.

Induced levels of climatic elements, either singly or in combination, such as temperature, humidity, air pressure etc. Materiel may be required to survive or to continue to operate when subjected to these induced environments, and therefore, must be designed to do so up to acceptable levels of risk.

Temperature Solar radiation, heat dissipation from nearby materiel, air conditioning in compartments, and thermal shock, in addition to other factors, contributes to increased and decreased induced temperatures. Depending on their locations on platforms, materiel items or components may experience wide-ranging direct or indirect induced temperatures in excess of outdoor ambient levels during transportation, storage, handling and use.


Solar radiation has a direct temperature elevating effect on outer surfaces of materiel. Temperatures in the enclosed areas may be alleviated by ventilation or forced-air cooling, or alternatively, aggravated by heat from operational equipment. High temperatures experienced by materiel installed within the frames of their platforms are likely to exceed the local ambient conditions because of indirect effects of solar heating of the platform structure or by absorption of heat emitted by the platform power units.

Temperatures of equipment installed in racks and instrument panels are likely to be influenced by self-dissipated heat and heat from adjacent electronic units and electrical power supplies.

Conversely when materiel is operating in cold regions, non-heat-dissipating materiel installed in enclosed compartments, stored under cover on external platform areas, may experience temperatures lower than the external ambient conditions, because the aeectp surfaces or enclosures are often better radiators to the night sky than the ambient air. Temperatures in Fully Air-conditioned Compartments Temperatures in fully air-conditioned compartments on or within platforms are controlled to provide a comparatively benign environment.

Each compartment should be assessed to determine if individual items of materiel are located aechp semi-stagnant areas where the temperature could fall outside the range of the controlled conditions. Temperatures experienced by individual units and components in electronic cabinets, racks, and consoles will depend on localised levels of dissipated heat and the provision of dedicated supplies of cooling air.

Temperatures in Partially and Non-conditioned Compartments In partially- and non-conditioned compartments, temperatures may be moderated by fresh air ventilation, by a supply of warm air aetp. Some items of materiel may be located in refrigerated areas. Thermal Shock During transportation, storage, or phases of service life, materiel may experience wide-ranging induced temperatures in excess of local ambient conditions.

Some materiel may be subjected to fast transient temperatures or thermal shocks. Such transient temperatures may be generated when materiel is handled from inside a shelter to out-of-doors or conversely.

Examples are materiel that is moved into cold outdoor ambient environments from a comparatively hot storage area. A converse example is materiel that is exposed to direct solar radiation before immersion into water. Humidity Temperature, air conditioning in compartments, and atmospheric pressure differentials are factors contributing to induced levels of humidity and moisture accumulation.

Effects of Heat on Aecyp The factors responsible for induced high temperatures inside shelters or under temporary covers exposed to direct solar radiation are likely to raise the moisture content of the enclosed atmosphere above external ambient conditions.

Humidity in Fully Air-conditioned Compartments The moisture content of the atmosphere in air conditioned compartments is normally controlled to provide comfortable and optimum working conditions for crew and installed equipment.

In the event of a breakdown of the supply of conditioned air, the introduction of external ambient air at a higher temperature and relative humidity can result in condensation and accumulations of moisture on the surfaces of installed materiel e.


Humidity in Partially and Non-conditioned Compartments The ambient conditions in partially and non-conditioned compartments can range from a dry heat to a damp heat environment. Factors influencing conditions include the level of ventilation and operational machinery contained in the compartment.

Heat generated by engines and electrical power generators is likely to reduce levels of relative humidity, while condensation and steam in air conditioning plants, galleys and laundries are likely to elevate relative humidity. Without adequate ventilation, the diurnal variations in solar heating aecp ambient temperature, plus the self-induced heating and cooling that aeectp during operation and following switch-off, can induce differential pressures causing materiel to breathe in and entrap moisture from the external atmosphere.

This phenomenon is evident particularly in humid tropic regions and applies to materiel under covers, to shelters, and even to otherwise sealed electronic units. Conversely, extremely low levels of relative humidity may exist in localised areas of equipment when dissipated heat adds to the drying effects prevailing in hot, dry regions of the world.

AECTP – What does AECTP stand for? The Free Dictionary

Condensation may occur on materiel when moved from a cold area to a hot area because of the difference of temperature. Similarly, moisture may enter and condense within compartments and individual materiel during descent from altitude to ground level. Under certain conditions of temperature and humidity, hygroscopic materials in an enclosure may release moisture to the air and this moisture can subsequently condense on the internal surface of the enclosure causing accumulation of water.


Air Pressure Altitude, compartment differential pressure, blast, and rapid decompression are factors contributing to induced levels of air pressure.

Elevated Land Areas Materiel aecpt hand-carried or mounted materiel may experience low air pressure levels that alter materiel effectiveness at high altitudes. Pressure tight components aecctp pressure relief mechanisms may awctp of value to maintain materiel performance and reliability.

Altitude above Sea Level aextp. Materiel transported in aircraft is required to survive or function at air pressures above and below normal ground zectp determined by the location of the materiel on the flight platform and by the flight profile. Aircraft compartments may be pressurised to limit and maintain compartment atmosphere at acceptable pressures equivalent to a nominal altitude above sea level.

Such compartments include cockpit or cabins that are occupied by the crew or passengers and cargo bays or areas that house avionics or other items specific to the operation of the aircraft or air-carried stores.

Materiel carried in unpressurised aectpp will be subject to prevailing ambient pressures at flight altitudes. Also, during take-off and landing or as a result of flight manoeuvres, rates of change of pressure far in excess of those arising from meteorological conditions may 2300.

Frontal areas and leading edges of externally carried stores on aircraft will be subject to dynamic pressure during flight.

Air pressure transients above normal ground ambient aect; be experienced by externally fitted materiel subject to blast from battlefield explosions. Internally fitted materiel located in pressurised compartments will be subject to steady values of overpressure during ground pressurisation tests.

Materiel deployed on fixed wing aircraft is required to survive or function at air pressures above and below normal ground ambient determined by its location on the flight platform and the operational scenario. Aircraft compartments may be pressurised to limit and maintain the atmosphere at an acceptable pressure equivalent to a nominal altitude above sea level, e.

Materiel carried in un-pressurised areas will be subject to the prevailing ambient pressure at the flight altitude. Also, during take-off and landing or as a result of flight manoeuvres, rates of change of pressure far in excess of those arising from meteorological conditions may occur 3. Compartments of vehicles may be 23. Therefore, levels of pressure may be different from those arising from meteorological conditions.

During storage, compartments of shelters may be pressurised above outdoor ambient levels. The compartment level is then maintained above that of the external ambient pressure by an amount known as the differential pressure. Handling may require compartments to be depressurised or may result in unexpected depressurisation.

Normally during flight, materiel installed in pressurised compartments will experience air pressures ranging between local ground ambient and some lower value equivalent to that at a predetermined altitude, say m.

Alternatively, materiel installed in unpressurised areas will be subject to the ambient air pressure at the flight altitude. Rates of Change of Air Pressure 3. Normal Operational Transient Changes a. It may be necessary for some items of materiel to remain installed during routine high pressure testing of submarine compartments.

ProMIL 150 NATO Stretcher Platform

Air pressure within the hull may rise above standard ambient while submerged, especially when firing a salvo of weapons. Materiel installed or carried inside the pressure hull is likely to be subjected to cyclic variation in air pressure below standard ambient during snorting. Positive and negative rates of change of pressure during flight sorties vary from those resulting from normal take-off and landing. Rates of change experienced by carried materiel depend on aircraft performance, the flight or mission profile and whether the materiel is 320 in a pressurised sectp non-pressurised area.

Operational roles of aectl winged aircraft preclude the need for pressurised compartments. Pressure levels experienced by deployed materiel are the prevailing ambient conditions at all stages of operation. However, rates of change of pressure will invariably exceed those resulting from meteorological conditions and will be determined by rates of climb and descent of the flight platform. Externally deployed materiel may experience overpressure caused by blast from explosions, gunfire and efflux from weapons fired or launched from the aircraft.