Some clients have their processes/storage in the middle of a neighborhood, and I mean in the middle of a neighborhood, as we see on TV and postcards. Beautiful tree-lined streets with kids riding their bikes and moms pushing their baby strollers. Of course, the facility came first, in the 1950’s, and then the encroachment. As a safety engineer, it is not my job to judge who is right or wrong; I’m hired to identify risks and offer solutions. And ss many of you know, I am a big proponent of using the International Fire Code (IFC) when OSHA has failed to address specific hazards. I simply hate using the “General Duty Clause” (5a1) when I can find a reference/solution in the IFC/IMC/IBC.
Most of my clients are chemical facilities that handle, store, and process Toxic and Flammable Liquids and Gases. Unfortunately, OSHA is way behind in making its standards on these hazards relevant to today’s businesses, so I am always working in the IFC, Chapters 50-61. Note: I do not do work in reactives, which are covered in Chapters 62-67. Recently, we came across a “facility siting” issue related to 20% Aqua Ammonia Storage. This material will actually fall under BOTH a “toxic liquid” (Chapter 60) and a “corrosive liquid” (Chapter 54), and just to be clear, all hazardous materials start with meeting the requirements found in Chapter 50 – HAZARDOUS MATERIALS—GENERAL PROVISIONS.
In chapter 60, section 2.3.1 Location, the facility is RESTRICTED just where “outside” they can store their “toxic liquid”…
6003.2.3.1 Location
Outdoor storage or use of highly toxic or toxic solids and liquids shall not be located within 20 feet (6096 mm) of lot lines, public streets, public alleys, public ways, exit discharges or exterior wall openings.
A 2-hour fire barrier without openings or penetrations extending not less than 30 inches (762 mm) above and to the sides of the storage is allowed in lieu of such distance.
The wall shall either be an independent structure, or the exterior wall of the building adjacent to the storage area.
In these older facilities, space is at a premium, but this restriction is KEY to ensure the general public is not impacted by this “toxic/corrosive liquid”. The client could not meet the 20′ restriction, and the chain-link fence did NOT provide the required barrier, so we replaced it with a 12′-tall concrete block wall. This exceeded the code and also prevented the prying eyes of neighbors who had, in the past, called authorities about matters they had observed when walking/driving by. The wall also acted as an “odor barrier,” for which the facility had received many complaints from neighbors. So a simple, inexpensive block wall solved many issues for a business that was growing tired of neighborhood complaints and false allegations of injury to neighbors. Since the wall was built in 2019, the business has received one (1) complaint, which was deserved; there has been a 95% reduction in complaints, and the local AHJ was ecstatic that they took action!
See, meeting basic code compliance can have positive outcomes!
FYI: Concrete block (CMU) walls provide exceptional fire resistance, typically ranging from 1 to 4+ hours depending on thickness, aggregate type, and grout filling. Standard 8-inch hollow blocks typically achieve a 2-hour rating, while 12-inch or fully grouted blocks can achieve a 4-hour rating. Source: https://www.nwcma.org/wp-content/uploads/2017/07/ConcreteMasonryFireResistanceJune2016.pdf