SwinnyGG
Mechanical
- Jan 22, 2016
- 2,581
Hey y'all.. I felt like this sub section was the most applicable for this question. I apologize in advance is this is better placed elsewhere.
So, on to the story- I am currently involved in an automotive plant construction/renovation project involving the installation of a clean-sheet new automated paint line. I'm locked in a debate with the customer involving the safety systems and egress paths required in the paint booths in order to meet NFPA/IFC codes. I'm creating this post to ask for a bit of a sanity check on my interpretation of NFPA 33/IFC.
Each line of this paint shop consists of multiple 'cells', which in turn consist of multiple booths linked in series and sharing a common conveyor, which operates as a stop-station system. Each cell contains, in order: manual booth for tac/wipe/primer inspection before painting (no sprayed coatings applied) -> manual door cut-in booth (sprayed by standard wall-bulkhead HVLP guns, paint mixing/storage outside the booth) -> robot-sprayed base coat zone (2 robots)-> robot sprayed clear coat zone (2 robots)
Between each booth is a two-panel automated sliding door.
In our as-submitted design, each sliding door contains 1 standard size non-latching man door to permit fire/emergency egress. Each man door has safety-rated, interlocked switches sending bits back to the safety PLC, along with the standard complements of light curtains and other personnel intrusion measures.
Basically, the problem I am dealing with is that the customer is trying to convince us that we can eliminate the intermediate man doors between the robot zones. This probably sounds minor, but between door hardware, switches and other electronics, controls, and programming, this represents a reasonably large cost reduction.
My interpretation of both NFPA 33 and IFC chapters 9/10/15/27 is that, assuming the booths are classified as H-2 occupancy, is that two exits are required per both the egress path length limit (booth is >25 feet) AND the occupancy load limit (booth is ~550 sq ft).
The fire suppression systems in this booth vary- some use a deluge system, while others use standard sprinklers. In all cases, when the fire system is activated the conveyor is e-stopped and the sliding doors, if in any other state than fully closed, are closed by the safety PLC.
Also, any time there are personnel inside a robot zone, performing maintenance or robot teach or whatever, the sliding doors are open and the entire system is in a protective stop condition.
The customer is stating that because the sliding doors are open when personnel are inside the booth, the intermediate man doors are unnecessary because they have two means of egress.
My point of view is that NFPA and IFC do not seem to distinguish between continuously occupied and intermittently occupied areas, and that based on egress path length and booth size, two exits are required with no exceptions.
So, sorry for the long post here.
Who is reading the codes correctly?
So, on to the story- I am currently involved in an automotive plant construction/renovation project involving the installation of a clean-sheet new automated paint line. I'm locked in a debate with the customer involving the safety systems and egress paths required in the paint booths in order to meet NFPA/IFC codes. I'm creating this post to ask for a bit of a sanity check on my interpretation of NFPA 33/IFC.
Each line of this paint shop consists of multiple 'cells', which in turn consist of multiple booths linked in series and sharing a common conveyor, which operates as a stop-station system. Each cell contains, in order: manual booth for tac/wipe/primer inspection before painting (no sprayed coatings applied) -> manual door cut-in booth (sprayed by standard wall-bulkhead HVLP guns, paint mixing/storage outside the booth) -> robot-sprayed base coat zone (2 robots)-> robot sprayed clear coat zone (2 robots)
Between each booth is a two-panel automated sliding door.
In our as-submitted design, each sliding door contains 1 standard size non-latching man door to permit fire/emergency egress. Each man door has safety-rated, interlocked switches sending bits back to the safety PLC, along with the standard complements of light curtains and other personnel intrusion measures.
Basically, the problem I am dealing with is that the customer is trying to convince us that we can eliminate the intermediate man doors between the robot zones. This probably sounds minor, but between door hardware, switches and other electronics, controls, and programming, this represents a reasonably large cost reduction.
My interpretation of both NFPA 33 and IFC chapters 9/10/15/27 is that, assuming the booths are classified as H-2 occupancy, is that two exits are required per both the egress path length limit (booth is >25 feet) AND the occupancy load limit (booth is ~550 sq ft).
The fire suppression systems in this booth vary- some use a deluge system, while others use standard sprinklers. In all cases, when the fire system is activated the conveyor is e-stopped and the sliding doors, if in any other state than fully closed, are closed by the safety PLC.
Also, any time there are personnel inside a robot zone, performing maintenance or robot teach or whatever, the sliding doors are open and the entire system is in a protective stop condition.
The customer is stating that because the sliding doors are open when personnel are inside the booth, the intermediate man doors are unnecessary because they have two means of egress.
My point of view is that NFPA and IFC do not seem to distinguish between continuously occupied and intermittently occupied areas, and that based on egress path length and booth size, two exits are required with no exceptions.
So, sorry for the long post here.
Who is reading the codes correctly?