# What is transmissivity testing?

## What is transmissivity testing?

LNAPL transmissivity is fundamentally a description of the relationship between LNAPL drawdown (or gradient) and LNAPL discharge (or flow). As such, most field test methods involve inducing an LNAPL drawdown at a well and measuring LNAPL discharge from the formation to that well.

## What is a baildown test?

Baildown testing is one method to measure LNAPL transmissivity. Detailed procedures to conduct and analyze baildown testing are provided in ASTM E-2856(2013). API sponsored development of this short (14 minute) training video discussing procedures to conduct a successful baildown test for unconfined LNAPL.

What is the unit of transmissivity?

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times foot of aquifer thickness [(ft3/d)/ft2]ft.

What is a transmissivity?

Transmissivity describes the ability of the aquifer to transmit groundwater throughout its entire saturated thickness (Figure 7). Transmissivity is measured as the rate at which groundwater can flow through an aquifer section of unit width under a unit hydraulic gradient.

### What is transmissivity used for?

Transmissivity is typically used to determine the water that an aquifer can deliver to a pumping well. It can be calculated directly from the aquifer’s average horizontal permeability and thickness.

### Why is transmissivity important?

Transmissivity of an IR Window is a critical data point when using IR cameras to inspect energized electrical assets. The transmission coefficient value of the window must be programmed into the IR camera to determine accurate temperature readings of a target.

How do you calculate transmission transmittance?

Transmittance refers to the amount of light energy that the glass absorbs, scatters, or reflects. It’s measured using the formula T = I/I0, with T denoting the transmission intensity, I indicating intensity, and I0 indicating intensity at the start.