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Limiting Oxygen Index

Limiting Oxygen Index


Model Number: SSI 515 LOI

Standard Number: ASTM D- 2863IS 13501

Critical Oxygen Index apparatus is used for determining the minimum percentage of Oxygen required to just support flaming combustion of a material at room temperature in FTA mode or at Higher Temperature (up to 400oC) in HFTA mode

 

Salient Features  
   
Oxygen Analyzer : Paramagnatic Dumb Bell Cell
Oxygen Readout : Digital, 0 to 100% , LC 0.1%
Temperature : Ambient to 400oC, LC 0.1oC
Gas Flow Indicator : Analog using Roto meter, 0-24 LPM, LC 0.5 LPM
Temperature Control : PID Controller, +/- 1oC
Gas Flow Control : Needle Valves,
   
Delivery  : 3 to 4 weeks
Packing  : Two Wooden Boxes (one for instrument and second for Glass Chimney) 
Alternate Model : SSI 515 LOID (with Digital Total Flow indicator LC 0.1 LPM)

Description

Instrument Principle

 

Critical Oxygen Index apparatus is used for determining the minimum percentage of Oxygen required to just support flaming combustion of a material at room temperature in FTA mode or at Higher Temperature (up to 400oC) in HFTA mode.

 

The sample is burned in the mixture of nitrogen and oxygen, and the percentage of oxygen required just to support the flaming combustion is recorded through an imported Oxygen Analyzer, which gives direct oxygen readings.

The apparatus also has a double walled test column of flame resistance glass of 75 mm dia. suitable for testing different size of samples in FTA or HFTA mode.

A digital temperature-indicating controller provided with the instrument controls the temperature for HFTA mode. The instrument is manufactured as per the ASTM specification and also confirms various other international standards.

Standard

The instrument conforms to ASTM D- 2863 and IS 13501.

 

Instrument

The instrument comprising of


    Paramagnetic Dumb Bell Oxygen Analyzer. (Permanent Sensor)
    Double walled glass test column with heaters.
     PID Temperature indicating controller.
    Flow meters and valves.
     Digital readout for Oxygen.
     Digital readout for Temperature.
     Roto meter for Gas Flow indication.
     L Shaped Burner for easy burning of samples.
     Sample Holder and hanger.
     ‘U’ Shaped Thermocouple to get the temperature at sample point.

The sample is ignited using the L shaped burner and oxygen % is adjusted till the sample starts to burn like a candle i.e. sustained burning without extinguishing or rapidly spreading the flame.  The Sample should burn in this condition for at least 3 mins. 

At higher temperature the requirement of Oxygen for combustion reduces. The environment around the sample is heated using double walled chimney with heaters for HFTA test. The procedure to determine the LOI remains the same as for ambient temperature. Reading are obtained for various temperatures and Oxygen % vs temperature graph is plotted.