What Drives Detection for Chemical Plant?

5/4/2023

What code or standard prescribes the location and/or number of heat / smoke / gas detectors needed for an industrial / chemical plant?

We have an open steel structure with processing equipment on most floors, which are essentially grating – no roof and no walls – containing flammable and toxic chemicals.

We’ve planned to place some detection in strategic spots downwind of the flare (southmost) and tankfarm (same flammables) and there are some single-story buildings and other outside equipment like a cooling tower, nitrogen generation, boiler – all downwind of the tankfarm and open structure mentioned.

So, some of all types where personnel could be in any area especially the lab/control room and electrical building mentioned above. The modular building supplier may have those taken care of but I need to check behind them.

The majority are outside and in the nine-story structure. I plan to have flame and gas detectors throughout depending on the correct guidance. Thanks in advance for your take!

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8 Comments

Greg

5/4/2023 09:26:08 am

Detection, suppression and other fire safety considerations for a chemical plant, like other industries, starts with local rules and requirements. Commonly referred to as regulatory requirements, legislation within State laws, AHJ regulations and local ordinances for permit and installation all form the primary rules for basis-of-design.

Chemical plants with activities including any use, storage, manufacturing, handling or the on-site movement of highly hazardous chemicals (HHCs) may fall under the rules of the Occupational Safety and Health Administration (OSHA) 1910.119 "Process Safety Management" (PSM)

Within PSM regulations, fourteen programmatic elements must be included within a HHC plant and its safety programs. Process equipment, tanks, piping and the movement of chemicals must be evaluated and include safety systems, such as interlocks, detection and/or suppression systems.

The selection, placement and overall level of protection of fire safety systems is required by OSHA to be determined through the method of Process Hazard Analysis (PHA). Within the PHA process, consequence is evaluated and using a hierarchy of controls, and ultimately set at a risk level. This process of PHA evaluation will commonly produce credited safety features, of which, fire suppression, gas detection, smoke/heat detection are inserted as a credited mitigating feature.

The overall reference to safety standards in the chemical process industry is referred to as RAGAGEP (Recognized And Generally Accepted Good Engineering Practices). The OSHA standard for Process Safety Management (PSM) requires that all equipment, inspections, and testing procedures comply with RAGAGEP. This leads to the third influence in the chemical industry for fire safety systems.

A publication that summarizes fire safety and hazard mitigation thinking within the chemical industry is, "Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon
Processing Facilities." This provides concepts for inclusion of fire protection that may be in addition to State and local rules, and includes the safety concepts of PSM, PHA and RAGAGEP.

The "Guidelines..." book is a needed reference for projects involving the chemical and hydrocarbon industry. Written by the Center for Chemical Process Safety (CCPS) and published by Wiley https://www.wiley.com/en-us/Guidelines+for+Fire+Protection+in+Chemical,+Petrochemical,+and+Hydrocarbon+Processing+Facilities-p-9780816908981

5/4/2023 09:46:01 am

As a further to the conversation above, if the placement of detection devices is not within the common requirements of NFPA or the manufacturer's instructions, it may be necessary to coordinate with engineers familiar with PSM hazard evaluations and the specific chemistries of the detectable products.

Using tools within the CCPS website may be highly beneficial. However, some of these tools will require assistance from members with access but may be necessary to properly solve the stated problem. https://www.aiche.org/ccps/tools

John T

5/4/2023 11:20:58 am

Don't forget to review the requirements of ISA/IEC code. ISA-84 has a risk base methodology for fire and gas detector placement. Good sites are ISA.org, Kenexis.com, Micropack fire and gas for starters. As suggested above a PHA is critical and should be considered prior to detailed design.

In addition, you may need to review insurance requirements.

Harmonization/application of these standards may require some creative/performance alternatives.

aviv link

5/4/2023 10:56:55 am

Agree with above regarding specific regulation, but note that if you're in a jurisdiction that adopts the IFC/IBC, you should to assess the quantity of hazmats and see if you're above MAQs. If so, you'd be dealing with a group H occupancy, which has its own set of requirements for detection (especially since your hazmats are toxic and flammables)

John ORourke

5/10/2023 12:08:06 pm

Aviv,

Can you specify where to find the group H occupancy requirements for detection? Thank you.

John

John D. Thomas

5/10/2023 04:28:21 pm

IBC references the IFC for specific fire alarm requirements.

I'm on the road with a bumb laptop, so here's a quick link http://www.firealarmsonline.com/2014/04/fire-alarm-for-group-H.html?m=1

But process plants should really be a risk/performance based on a risk analysis specific to the process. PHA is needed.

You should not be designing in a vacuum or with a100% prescriptive approach due to the hazard and the detection technology likely used.

Aviv link

5/11/2023 11:08:26 am

Hi John,

I agree with JT's comment that the system should not be designed in a vacuum. I recommend a full hazard analysis to be undertaken, if it hasn't been conducted already.
The requirements for Group H are located in chapter 4 of the IBC and chapters 50, and 51-67 of the IFC. However, "Group H" is not an occupancy in and of itself; your occupancy, and the consequent requirements - will be depended on the type of hazard you're dealing with. Group H3 (flammable liquids storage), for example, will have different reequipments than that of Group H2 (flammable liquid processing) or Group H4 (physical hazards, like toxics and corrosives). These occupancies are not directly related to the strictness of the regulation (i.e. H4 isn't stricter than H3), and when you have materials of multiple classes (like toxic flammable liquids), you must abide by the requirements of *all* types of Group H.
Also note that some requirements still exist even if you're below the MAQ (meaning, not a Group H but control areas strategy) - the requirements of IFC 5001 to IFC 5003 would still apply.

All that said, generally I'd start with:
1. check IBC 414 and IBC 415 to see if I have any general requirements,
2. evaluate my quantities to know if I exceed MAQs (because if so, the requirements of IFC 5004 and IFC 5005 apply)
3. apply IBC chapter 4 and requirements of the local jurisdiction
4. if above MAQs, apply IFC 5004 / IFC 5005, and the relevant chapters for my hazard (e.g. chapter 60 for toxics, chapter 54 for corrosives, etc.)

5/11/2023 11:20:52 am

Aviv,

100% agree. I trying to keep it short showing the relationship with the IBC's H occupanCIES and IFC. Well summarized.

Cheers

What Drives Detection for Chemical Plant?

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