The ammunition has an assigned shelf life which depends on its design and chemistry of propellants / explosives used, and is prone to deterioration / decomposition even under normal storage conditions. The author highlights the need for shelf life assessment…
For a Weapon system the serviceable ammunition logistic and operations costs comprise up to 70-80% of a systems life-cycle cost. Ammunition has certain unique characteristics that necessitate quality and reliability evaluation during design, production and storage life. All ammunition stored has an assigned shelf life which depends on its design and chemistry of propellants / explosives used. These are high energy materials thus inherently unstable and prone to deterioration / decomposition even under normal storage conditions. The designed shelf life is given as per the life of the subsystem which has the lowest shelf life under normal conditions of storage. However, the operational exposure of ammunition products varies and hence functional life may be different. Before we go on to address the issue of life cycle assessment, let us talk some basic issues specific to ammunition.
“The quality of ammunition deteriorates with ageing due to environmental factors, manifesting in changes to safety, reliability, and performance characteristics and during storage it has considerable economic as well as catastrophic consequences”
- Ammunition contains high-energy material and is designed to be as lethal as possible during its use and as safe as any other equipment during its use, transportation and handling.
- It is designed for optimum performance and manufactured under controlled conditions.
- The system mostly comprises of a combination of electronic, mechanical, chemical or structural sub systems, which cannot be fully tested in the integrated forms without partial or full destruction.
- The functioning of ammunition consists of irreversible reactions or a process. There is need for testing even the sub-systems independently before integration.
- The ammunition deterioration during storage has considerable economic as well as catastrophic consequences. The ageing ammunition assets can turn in to liability in case not properly cared. Hence, the exceptions during each stage must be predicted, detected, identified, and mitigated to prevent unacceptable risk involving safety and performance.
Ammunition is kept in storage in different depots for a considerably long period of time after production. The quality deteriorates with ageing due to environmental factors, manifesting in changes to safety, reliability, and performance characteristics. The ammunition deterioration during storage has considerable economic as well as catastrophic consequences as seen from the series of fatal accident world wide as well as in India.
Accidents during Storage in India
India is no exception. The improper stocking of ammunition without limits, holding of stock without inspection & turnover increases fire/accident risk in the depots. The situation has resulted into number of accidents in the depots in the recent past as given in the Table below.
Unserviceable ammunition is not an asset but a liability. In Indian context till recent past, the decision makers did not realize the consequences of holding Unserviceable Ammunition inventory and no serious thought was given to assess the exact quantity of Unserviceable Amn, leave aside the threat assessment posed by such inventory. As on date the conservative estimate is that the Indian Defence Services holds unserviceable Amn over 100000 MT. The unserviceable / obsolete ammunition with Indian Army have been increasing over the last few years. The ammunition stockpile will continue to grow until the resources are catered to maintain and expedite unserviceable ammunition disposal.
The ground situation was also highlighted in Controller and Auditor General (CAG) Report No. 7 of 2002 (1) that Ammunition Depot at Dhapar is holding 35,000 tones of ammunition against its authorized storage capacity of 12,000 tones. Similar is the conditions of other storage depots. Improper storage leads to faster deterioration. A large percentage of this ammunition has crossed the assigned shelf life due to various reasons such as improper assessment of shelf life, non utilization, various restrictions, improper turn over, excessive scales etc.
The Government took some measures for modernization of ammunition depots post 2002, however still a large quantity of Ammunition is stored under adhoc conditions.
Need for Shelf Life Assessment
In order to keep a track on the quality of ammunition during various conditions of storage, there is a need to predict the ammunition behaviour under different conditions. Quality evaluation (QE) during shelf life is a critical logistics element of the total life cycle incorporating both preventive and corrective maintenance elements to ensure the ammunition is kept in the highest state of readiness. Quality evaluation during life cycle to determine the current condition of the inventory entails test, surveillance, and prediction of the effects of ageing and environmental exposure on all in-service Ammunitions. It enhances the ability to analyze and predict the safety, reliability, and performance of ammunition using scientific data and trend analysis. The QE program will help in Identification of causative factors those originating from design, assembly, maintenance, handling, storage, deployment and interfaces with weapons and combat systems. Timely identification of potential deficiencies will provide information to make decisions required to optimally manage the ammunition inventory and procurement plans as well as determining maintenance requirements for ammunition by providing technical and statistics based evaluations. The present system of surveillance or visual inspection at depot and Proof is grossly inadequate to assess the remaining life without predictive technology. This responsibility can be taken over by DGQA organisation.
There is a need to develop Models to predict quality of ammunition at a given time and such models can also be used to control manufacturing process and depot storage conditions. The resultant predictive model can be used to determine the appropriate time for use, replacement or renovation of the ammunition. The task involved is time consuming and requires certain infrastructure. Controllerate of Quality Assurance (Ammunition) in the recent past has leveraged the data available to accord the status in some of the ammunition. The performance of Anti- Personnel Mine of
various vintages in the recent testing exhibited the pattern shown in Table and pictorial depiction of the same is shown in Figure. The best fit lines have been drawn for visual, chemical and proof performance. In order to get a general pattern a common failure lines has been drawn as shown in Figure. It is concluded at Anti Personnel Mines in regular storage (less Detonator) could be used up to 25 years of life as against 10 years specified.
Shelf Life Assesment Mine APNM-14
DGQA Organization has taken initiative to set up facility for
Life Assessment and Predictive Technology for ammunition, which is operational and only of its kind in India. There is need to have a team from the army's ordnance branch to be posted at this facility with all the details of stocked ammunition to interact closely with DGQA (Armaments) CQA (Amn) for ammunition related issues. The data collected by them will go a long way in developing such models, through Interaction with agencies concerned with design, development, production quality assurance & users, and will address safety concerns and other technical issues.