RAGAGEPs and "the numbers"Safety Info Posts - Chemical Process Safety (PSM/RMP)Written by Bryan Haywood   Wednesday, 19 June 2013 16:54

The use of Recognized and Generally Accepted Good Engineering Practices (RAGAGEPs) has become a common occurrence since OSHA's Process Safety Management standard and EPA's Risk Management Plan rule came out in the 1990's  Some professionals have come to hate RAGAGEPs and wish for the good ole days when OSHA promulgated prescriptive standards like 1910.23; and then there are others who work diligently to dissect the RAGAGEPS looking for every loophole they can possible find in order to do as little as possible in their attempt to comply with these baseline standards... and here lies the problem!  There are not many published RAGAGEPs that require some baseline expectations in their implementation; however, there are some in the process safety arena that will argue that if the RAGAGEP does not specifically require it (or prohibit it) then it is NOT required (or a violation of said code); but my position is with the RAGAGEPs come some basic expectations...

Take for example "ventilation" for a covered process.  Depending on the RAGAGEP chosen, there are numerous ways to design the ventilation system and NONE of these RAGAGEPs state the obvious in regards to fundamental ventilation designs.  We have come across some odd ventilation arrangements that we were challenged on that it was NOT a violation of the RAGAGEP since no one could not point to a sentence that prohibited the design basis from being what it was.  Here is an example of how a RAGAGEP can be bent and molded to meet some need - other than safety!  You tell me if you would take issue with something like this...

A facility has a covered process that has a portion of the process that is enclosed.  This enclosed area requires one of two critcial paths to be followed, with ventilation (i.e. engineering control) being one of those acceptable paths. During an expansion project on the process, it was determined that the project was going to require the ventilation of the enclosed space to be upgrade in order to remain complaint with the RAGAGEP the ventilation was designed to.  The problem arose when it turned out there was not enough available real estate to locate some of the process equipment associated with the process expansion.  One open area that was used was directly in front of the enclosed space's ventilation make-up air in take.  It was questioned by the facility, but the designer showed them "the numbers" that the ventilation met code (e.g. the numbers showed systems CFM was adequate for the size of the enclosed space).  But here are some items "the numbers" did not show:

1. the equipment being placed in front of the fresh air in take will contain several thousand pounds of the Highly Hazardous Chemical that the ventilation system is meant to evacuate from the enclosed process area

2. the equipment being placed in front of the fresh air in take is also "fan driven" and will be "competing" for the same air as the fresh air in take

3. the equipment is approximately 4X's the size of the fresh air intake and covers the entire face of the in-take, albeit between 6-8' away.

The moral of this story (and it is a true story) is that REGARDLESS of what "the numbers" tells us, things have to make sense in the field.  We must have the design basis for our ventilation systems documented and this documentation should include the basics:

1. how much air the system can move,

2. how it will move it,

3. where the make-up air will come from,

4. where the dirty air will discharge to,

5. set points for activation, etc.  

Everything can be shown on paper as being just peachy cream... however, a brief walk through of the process could become problematic when the inspector/auditor sees a piece of equipment with a surface area ~4X's the size of the fresh air in take directly in front of the intake.  REGARDLESS of what "the numbers" may say, the very basic premise of industrial ventilation is that airflow, both make up and discharge, NOT be restricted.  Placing a large piece of equipment in the air path of the in-take may not be specifically spelled out in the RAGAGEP and may not

be reflected in the calculations, but it is NOT meeting the RAGAGEP.  Throw in the fact that we have now placed our HHC/EHS directly in the path of the "fresh air" in take is just adding more pain to the design argument.  The fact that this large piece of equipment will also be fan driven and it has multiple fans moving MORE air than the enclosed ventilation system is just beyond what I can logical understand the designers arguement that "it is to code".  It matters NOT one bit what "the numbers" state, this "design" is not going to meet the needs of the facility and COULD possible create a major problem for the facility should the equipment begin to leak the HHC/EHS.  In fact, I challenged the designer to demonstrate via smoke test that the discharge from the enclosed space will be strong enough to overcome the pull from this large piece of equipment, which is not too far from the ventilation discharge, meaning we could have a recirculation of bad air if the piece of equipment contines to operate during a leak of the HHC/EHS.  Current design does NOT include an interlock to shutdown this piece of equipment if there is a leak; which may become mandatory for the ventialtion to pass the smoke test.

Moral of the story... RAGAGEPS are not perfect and were not written to cover every base that someone could conceivably defeat.  Regardless of what "the numbers" say, the true test is will it WORK AS DESIGNED.  This situation I have serious doubts... what say you?  Does this ventilation system design and facility siting of covered process equipment meet RAGAGEP?