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IS 10053:1981 is the Indian Standard (BIS) for requirements for equipment for jackson candle turbidimeter and determination of turbidity. This standard specifies the requirements for the Jackson candle turbidimeter apparatus and outlines the procedure for determining turbidity in water. The method is based on measuring the length of the light path through a water sample at which the image of a standard candle flame just disappears. It is suitable for turbidities between 25 and 1000 JTU.
Requirements for equipment for Jackson candle turbidimeter and determination of turbidity
! This is a historical and visual method, highly dependent on the operator's eyesight and judgment. It is largely superseded by modern, more precise nephelometric methods (see IS 3025 Part 10) that measure in NTU.
! The method is not suitable for low turbidity water, such as potable water, as its lower detection limit of 25 JTU is well above the acceptable limits (typically < 1 NTU).
! Proper maintenance is crucial; the bottom of the glass tube must be kept perfectly clean and unscratched, and the candle must be maintained at the correct height.
Directly specified the Jackson candle turbidimeter method alongside nephelometric methods.
APHA 2130A (20th Edition, 1998)APHA/AWWA/WEF, USA
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Standard Methods for the Examination of Water and Wastewater, Method 2130A: Turbidity (Visual Methods)
Provided detailed procedures and apparatus specifications for the Jackson candle method.
ISO 7027-1:2016International Organization for Standardization, International
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Water quality — Determination of turbidity — Part 1: Quantitative methods
Specifies determination of turbidity but mandates a modern nephelometric (90° scatter) or turbidimetric (light attenuation) instrumental method using an infrared source.
Key Differences
≠IS 10053 is based on the principle of light extinction (visual disappearance of a candle flame), whereas modern standards like ISO 7027 are based on nephelometry (instrumental measurement of light scattered at 90°).
≠The unit of measurement in IS 10053 is the Jackson Turbidity Unit (JTU), which is subjective and not reliably convertible. Modern standards use Nephelometric Turbidity Units (NTU) or Formazin Nephelometric Units (FNU), which are instrument-based and more reproducible.
≠The Jackson candle method described in IS 10053 is unsuitable for low turbidity water (below 25 JTU), while modern nephelometric methods can accurately measure turbidity well below 0.1 NTU.
≠IS 10053 specifies a natural silica or diatomaceous earth suspension for calibration, whereas modern standards like ISO 7027 mandate a more stable and reproducible formazin polymer primary standard.
≠The Indian Standard relies on a standard beeswax and spermaceti candle as a light source. Modern standards specify precisely controlled light sources, such as a tungsten lamp (USEPA 180.1) or an 860 nm infrared-emitting diode (ISO 7027).
Key Similarities
≈Both IS 10053 and its international counterparts share the fundamental purpose of quantifying the optical clarity of water as affected by suspended particles.
≈The basic apparatus concept involves a vertical transparent tube holding the sample through which a light source is viewed or measured, establishing a relationship between water depth and turbidity.
≈All standards, historical and current, rely on the principle of calibrating the instrument or method against a standard suspension of known turbidity.
≈General sample handling procedures, such as ensuring the sample is representative and well-mixed before measurement, are common across all methods for determining turbidity.
Parameter Comparison
Parameter
IS Value
International
Source
Measurement Principle
Visual light extinction
Nephelometry (90° light scatter)
ISO 7027-1:2016
Primary Measurement Unit
JTU (Jackson Turbidity Unit)
FNU (Formazin Nephelometric Unit)
ISO 7027-1:2016
Lower Detection Limit
25 JTU
25 JTU
ASTM D1889-00
Primary Calibration Standard
1 g/L Silica (Diatomaceous earth) suspension
Formazin polymer suspension
ISO 7027-1:2016
Light Source
Standard candle (beeswax and spermaceti)
Standard candle
APHA 2130A (20th Ed.)
Modern Light Source
Not Applicable
Radiation source with a spectral band-width peak at 860 nm (infrared)
ISO 7027-1:2016
Tube bottom material
Flat, polished, plane-parallel glass bottom
Flat, polished-glass bottom
ASTM D1889-00
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Measurement PrincipleDisappearance of candle flame image through a column of water
Unit of MeasurementJackson Turbidity Unit (JTU)
Lower Detection Limit25 JTU
Upper Measurement Limit1000 JTU
Standard Suspension MaterialFuller's Earth or Diatomaceous Earth (Silica)
Standard Suspension Concentration1 g/L corresponding to 1000 JTU
Tables & Referenced Sections
Key Tables
Table 1 - Graduation of Jackson Candle Turbidimeter
What is the unit of measurement for turbidity in this standard?+
The unit is the Jackson Turbidity Unit (JTU).
What is the working principle of the Jackson Candle Turbidimeter?+
It works on the principle of light absorption. The turbidity is determined by the depth of water required to make the image of a standard candle flame just disappear when viewed from the top.
Why is this method not used for drinking water testing?+
Because the permissible turbidity for drinking water (e.g., 1 NTU per IS 10500) is far below this method's lower measurement limit of 25 JTU.
What is the difference between JTU and NTU?+
JTU is based on light absorption (Jackson Candle method), while NTU (Nephelometric Turbidity Unit) is based on light scattering measured at 90 degrees to the incident light beam, which is a more sensitive and objective method.