Research Article
Fire Investigation in an Industrial Grade Nitrocellulose Plant
Murthy TSN*, Baggi TR, Hiren NJ and Harika K
Corresponding Author: Murthy TSN, AP Forensic Science Laboratory, Hyderabad, India.
Received: January 05, 2022; Revised: February 11, 2022; Accepted: February 14, 2022 Available Online: February 24, 2022
Citation: Murthy TSN, Baggi TR, Hiren NJ & Harika K. (2022) Fire Investigation in an Industrial Grade Nitrocellulose Plant. J Forensic Res Criminal Investig, 3(1): 110-115.
Copyrights: ©2022 Murthy TSN, Baggi TR, Hiren NJ & Harika K. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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An incident of fire was reported in an industrial grade nitrocellulose manufacturing unit. Forensic investigation was carried out to find the cause of fire. The scene of fire was thoroughly examined and searched for the evidence. Partially burnt samples of debris and burnt electrical wires were collected from the scene of fire. The GC-MS analysis of the debris revealed the presence of hydrocarbons belonging to fire accelerants. A study of CCTV footages revealed the origin and time of fire. Basing on the findings and the information gathered during field visit, it was opined that the incident of fire was caused due to human intervention.

Keywords: Nitrocellulose, Industrial grade, Isopropyl alcohol, Butanol, GC-MS

INTRODUCTION

Nitrocellulose consists of two grades viz., Propellant grade containing more than 12.5 % nitrogen used for production of smokeless gun powders and Industrial grade containing less than 12.5% nitrogen and employed as a film-forming agent in solvent-based paints, protective coatings, fingernail polishes etc. Nitrocellulose (Figure 1) is a derivative of cellulose and is manufactured from purified cellulose either in the form of cotton linters or wood pulp. The manufacturing process involves nitration of purified cellulose with nitric acid and Sulphuric acid under controlled conditions followed by stabilization and washing.

The fire affected plant manufactures industrial grade nitrocellulose by removing water from wet nitrocellulose by centrifuging and adding a solvent such as isopropyl alcohol/butanol. Wet nitrocellulose with nitrogen content in the range of 10.7% to 12.2% is taken as raw material.

Pallets carrying these drums are transferred to the designated storage area. Tankers carrying solvents- isopropyl alcohol/butanol are unloaded in MS storage tanks. During centrifuging process, the industrial wet nitrocellulose is manually taken in open top HDPE drums and using SS bowls, the centrifuges are charged. The centrifuge machine is operated between 500-900rpm for the desired duration. After obtaining the desired moisture content of 2-3%, isopropyl alcohol/butanol is mixed vigorously by using wooden shovel manually. Once the industrial damped nitrocellulose becomes ready, it is packed into corrugated/MS drums. According to security guard, he closed and locked the plant at 10:00pm as usual after the night shift. In the early hours between 03:00 to 03:30 am on the fateful day, he heard some crackling noise and immediately got alerted and rushed to investigate when he noticed huge flames and smoke emanating from the manufacturing area of the plant. He informed the fire brigade which reached in the next 25 min and brought the flames under control by 9:00 am. There was no explosion and there were no casualties in the incident.  The factory (with RCC roofing) consisted of two halls, one on the northeastern side (13mx16m) meant for raw material storage area and the adjacent hall (15mx22m) called manufacturing area where three centrifuges were arranged adjacent to the southeastern wall. Behind the manufacturing area of the RCC building and the southeastern compound wall, working shed (15.5mx4m), with GI sheets roofing was located and contained one air compressor unit, two oil units & electrical panel board. Dyke wall of height 0.60 m was present behind the southwestern area where four tanks (one for Butanol 20 KL, one for I.P.A. 20KL and two solvent storage tanks each of capacity 30KL) were located. On the southwestern side of the manufacturing area finished material storage area (22mx25m) with GI Sheeted roof was located as shown in Figure 2 below.

OBSERVATIONS & FINDINGS

In the raw material storage area, finished products (solvent nitrocellulose) in different sizes of drums were stored in addition to raw material (wet nitrocellulose). All the material stored in the storage area was found to be partially burnt (Figure 3).