Back to the Basics: The Steady State

In order to determine the suitability of a particular analyzer system, it is useful to study potential process upsets. 

There are two main types of process upsets that could present a hazardous condition: 

  1. The steady-state (approximately time invariant) 
  2. The transient (time sensitive)

Of these, the transient upset condition poses the greatest difficulties in detection and correction. But before we get to that let's look at the steady-state conditions:

Back to the Basics: Safe reduction of ventilation

Last week we discussed the 2 cases at which the authorities have determined that certain industrial processes can proceed at solvent vapor concentrations up to, but not exceeding, some percentage of the Lower Flammable Limit.

Let’s focus on case #2: What happens when an analyzer and control system are used? 

Back to the Basics: Limits to solvent vapor concentration

The authorities have determined that certain industrial processes can proceed at solvent vapor concentrations up to, but not exceeding, some percentage of the Lower Flammable Limit. 

In general, there are two cases:

  1. The fundamental safety limit
  2. The limit when an analyzer and control system are used

This week let's take a look & expand upon Case #1: Fundamental ventilation requirements.

Back to the Basics: Temperature Effects on LFL

So we know what the LFL is and how it's determined, but what about the factors that can effect these values?