JSS (Revision No. 1) MINISTRY OF DEFENCE JOINT SERVICES SPECIFICATION ON ENVIRONMENTAL TEST METHODS. JSS , knowns as the Penta-Five test, is an antifungal product test for electronics. JSS Revision No. 1. LIST OF MEMBERS ASSOCIATED WITH FORMULATION OF THIS STANDARD. 1. This Joint Services Specification has.
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Post on Nov views. Date Amendment pertains to: The term Equipment for the purpose of this specification, shall mean Missile and Missile borne systems. It dose not apply to support equipment.
The sjs described herein are not to be interpreted an exact and conclusive representation of actual operational and storage conditions. It is also the purpose of this document to standardize environmentalists in order to obtain, as much as possible ,reproducible test results. In some of the tests, the test conditions are varied in order to enable the designers select the conditions which will be adequate to meet the users qualitative requirementscommensurate with the design efforts.
The relevant equipment specification shall define the acceptable performance limits during and after the specified environmental tests. Such instructions, together with the incidence and grouping of equipments for tests for the purposes of design approval and the acceptance inspection shall be specified in the relevant equipment specification.
While conducting any test described in Section 4 of this specification, standard procedures and conditions of tests shall be followed see 1. In such cases the details shall be as given in the relevant equipment specification.
Environmental Testing of Armament and Packages. In practice it is taken as the average of temperatures measured at a number of points in a horizontal plane through a point 0 mm to 50 between the equipment and the wall of the tes chamber or at 1 m distance, whichever is less. IF js circulation is used in the testing of heat dissipating equipment, the concept of ambient temperature is no longer valid.
Under these conditions, the testing should be based these conditions, the testing should be based on the specification of the surface temperature or the requirements of the relevant equipment. Final measurements made at the end of test may be taken as the initial measurements of the subsequent test. Measurements required to prove that an equipment can be regarded as non- heat dissipatingcan be made in normal laboratory conditionsif care has been taken that no outside influence for exampledraughts or sunlight affects the measurements.
Where called for ,it is the first process kss the test procedure. For heat dissipating equipment it is necessary to make repeated measurements to ascertain in interval of time required for the temperature to change3 deg c or as otherwise specified. Temperature stability has been reached when the ratio between consecutive intervals exceeds 1. Where the thermal time constant of the equipment is of the same jsx as the duration of the exposure ,checks should be made to ascertain;A a The non heat dissipating equipments are within the required limit from the mean in time temperature of the atmosphere in which the equipment is placed.
In practiceit may not be possible to make direct measurements of the internal temperature of the equipment. A check may then made by measuring some other parameter which is temperature dependent and for which the law of temperature dependent is known. Test Chamber – An enclosure in which the equipment environmental test conditions.
During the visual examination of kss equipment, defects in construction, the presence of foreign bodies, moisture, dust ,etc. Temperature Air pressure 20c No requirement for relative humidity is given because its correction by calculation is generally not possible. In such casesthe actual values used jsz be given in the test report.
JSS_ – [PDF Document]
Temperature Relative humidity Air pressure 15 c to 35 c. The temperature range may be extended beyond these limitsup to 10 c to 40 c for large equipment. The limits of variation of temperature and relative humidity carried during a series of measurements carried out as part 011 one test on any equipment shallif necessarybe specified in the relevant equipment specification. It isthereforeessential to refer ,before caring out a test02256 the relevant equipment specificationto ascertainif any modificationshave been in the test conditions.
For this purposethe volume of the test chamber should preferably be not less than eight times the volume of the equipment under test. These sensors shall be centrally located within the test chamber, where possibleor in the return air stream and shall be baffled or otherwise protected against direct impingement of supply air and against direct impingement of supply air and against radiation effects.
The air in the chamber shall be continuously agitated but 0 so vigorously as to cause undue cooling of the equipment under test. Most of the equipments have restricted sphere of use whichby limiting the severity conditions of usemay aloe simplification of the design with the restaurant jes in cost. The severity under various conditions largely iss on their deployment conditions, role for which it is designedthe location of the equipment in the missileand factors like permissible modes of transportation.
Conventional classification based on rangerole etc. For example a short range missile like anti call for high altitude test ,if permitted to be airlifted. Even then it will be desirable that the containers with missiles in positions are tested for the altitude and rapid temperature cycling.
Applicability for a particular equipment is to be decided by the designer in consultation with users and inspection Authority taking all relevant factors into account. Guidance js selection of levels will be given appropriately in this document for selection. Missiles framepropulsion nss, liquid systems Hydraulic systems ,gas 10 and mechanical equipment having only mechanical Equipment having only mechanical 026 parts.
Electronic equipments Complete missile. Group V Group VI2. Tests required for each group and recommended sequence of tests are given in table 3. The relevant equipment specification should choose only those tests out of the table, which are considered applicable for the equipment under test. For sealed equipment this test may be applied only to components and finishes located outside the seal.
Separate equipment can be used for this test. Combination of hss tests may be resorted to by the designerif required. The chamber shall be capable of maintaining its working space at the appropriate high temperature severitywithin the following tolerances: The high temperature conditions in the chambers shall be achieved by circulating hot air and these conditions shall be maintained uniformlythroughout the working space of the chamber.
The heating element s of the chamber shall be baffled to prevent direct radiation on the equipment under test.
JSS 55555 – Antifungal Test – Electronics
The temperature within the chamber shall be monitored by a temperature sensing device suitably located in its working space. The design and construction of the chamber shall be such that any heat dissipated by the equipment during testing shall not appreciably influence the conditions within the chamber. The equipment under test shall be subjected to this test in un parked conditions. At the beginning of the test the equipment shall be in its Switched off” conditions.
The equipment under test being under laboratory atmospheric conditions shall be introduced in the chamber, the latter also being under the same conditions. The chamber temperature shall then be raised to 55 c. The temperature of chamber shall then be raised to 65 c. After this periodthe chamber temperature will be brought back to 025 c.
If required the equipment shall be switched on and operated for a specified duration at any ime during this period of exposure. Performance check shall be carried out at the end of each phase the maximum surface temperature attained by the component or materials in the equipment shall be measured and recorded, if required. The temperature of the chamber shall then be restored to laboratory atmospheric conditions. Recovery The equipment shall then be removed from the chamber and shall be allowed to remain under standard recovery conditions.
Final measurements The equipment shall then be visually examined and shall be subjected to electrical, mechanical and other checks, as specified. Duration of operation of equipment and the time at which this operation should commence see 3.
Any deviation from the normal test procedure. The chamber shall be capable of maintaining its working its working space within deg c of the appropriate low temperature severity. The design and construction of the chamber shall be such that any heat dissipated by the equipment during testingshall not appreciably influence the conditions within the chamber. Conditioning – The equipment under test shall be subjected to this test in un packed conditions.
Procedure The equipment under test while being in laboratory atmospheric conditions shall be introduced into the chamber the latter also being under the same condition.
The chamber shall then be lower d to one of the test conditions given below: The performance check shall be carried out during the last 30 minute of the period specified. The chamber temperature shall be restored to test conditions after performance check. At the completion of the test periodthe equipment shall be subjected to recovery conditions and final measurement shall be made as specified. The duration of operation of equipment and time at which this operation should be commenced see 3.
Performance check required during the test period. Any deviation from normal test procedure. In additionthe chamber shall also be capable of meeting all the requirements specified for test chamber for the high temperature test Test Number 1 and the low temperature test Test no 2.
The altitude chamber shall also be capable of maintaining a relative humidity of not less than 95 percent as required for procedure 2.
Conditioning The equipment under test shall be subjected to this test jas unpacked Condition. Two procedure are specified for this test. Procedure 1 This shall be carried out in seven steps.
Altitude ceiling for air transportation. Temp corresponding to height h. After test chamber conditions are stabilizedmaintain these test conditions for one hour. At jas end of this periodthe test item shall to the extent possiblebe visually inspected for presence of deterioration which would impair future operation.
Step 2 – Adjust the chamber test conditions to those specified in Step 2 of table 4. Step 3 – The chamber pressure shall be adjusted to the corresponding to one of the test conditions A1 to A4 Table 4. The performance check shall be carried out on the equipment as required.
Step 4 – Adjust the chamber pressure to one of the test conditions depending on altitude ceiling for air transportation. Adjust the chamber temperature to the corresponding temperature given in Table 4. Maintain the condition for 3 hours. Step 5 Adjust the chamber pressure corresponding to the one of the test conditions depending on altitude ceiling for operation.
Adjust the chamber temperature corresponding to the test conditions chosen as given in Table 4. Maintain the condition for 1 hour. The equipment shall then be operated as specified.
The equipment normally operated throughout the flight shall be operated from the start of the temperature conditioning and shall continue to operate throughout this step.