Storage occupancies have prevailed as being one of the most challenging and diverse environments in which to protect against fire. No other occupancy type involves such a wide range of hazards and variety of products stored under one roof. New materials and commodities, methods and arrangement of storage, building size and increased storage heights have all contributed to this fire protection challenge. Storage classifications have expanded, and storage and retrieval methods associated with these occupancies have changed dramatically. Fortunately, modern storage solutions can be protected by efficient and cost-effective fire protection solutions that could not be provided in the past with traditional spray sprinklers. Sprinklers designed with traditional orifice sizes, such as ½” and 17/32”, have had to be installed with supporting high-pressure systems where discharge densities of 0.34 gpm/ft2 and greater are required. Ceiling systems with these sprinklers usually required additional in-rack sprinkler protection because the ceiling sprinkler discharge did not provide water droplets with adequate momentum to reach the burning surfaces of the commodity at floor level. The sprinkler industry and testing laboratories have recognized that changes in the design of storage occupancies require updated means of fire protection. In addition, experience has shown that in-rack sprinklers were undesirable to building owners because of limited flexibility and maintenance issues, not to mention being subject to damage from various material handling methods.
Based on full-scale fire testing by manufacturers and consortium groups, the details of fire dynamics associated with different fuels and their arrangement are being learned and have been applied in the creation of new sprinkler technology. Laboratory capabilities accommodating new design parameters for fire testing, as well as knowledge gained from historical fire losses, have furthered these technical efforts. One of the most significant developments arising from research in the 1990’s was the development of the Early Suppression Fast Response Sprinkler (ESFR). An ESFR sprinkler was classified as a “suppression mode” sprinkler, rather than a control mode sprinkler. Control mode density area (CMDA) storage sprinklers are typically standard response sprinklers that rely on limiting the size of the fire by confining the fire to one area, wetting the combustibles in the surrounding space, and cooling the hot gases at the ceiling. Suppression-mode sprinklers use a fast-response thermal element so that they come into operation during the early stages of a fire. They deliver a large amount of water at high speed through the fire plume to the seat of the fire, and sharply reduce the rate of heat release.
With the use of ESFR sprinklers, building owners can be provided with adequate fire protection for a wide variety of commodity types and storage arrangements. Protection is sufficient in buildings up to 40’ and 45’ in height, using a ceiling-only sprinkler system with no in-rack sprinklers. The ESFR has a discharge orifice larger than traditional spray sprinklers, which is the key to its success: it has the ability to create larger droplets and deliver an increased volume of water. For many years, this has been the sprinkler of choice for most building owners, allowing the construction of buildings with one type of sprinkler system and minimal restrictions on tenant operations. Benefits unique to ESFR sprinklers include superior performance and operational flexibility in regards to changing commodities and storage arrangements. However, it is necessary to be aware of specific limitations in the application of ESFR sprinkler technology. The effectiveness of ESFR sprinklers is reduced by obstructions, and thus requires strict adherence to installation guidelines. In addition, ESFR technology may not be able to protect facilities housing certain types of plastic commodities.
This article was contributed by Firepoint Inc, serving the GTA since 1997, developing fire department approved fire safety plans for newly constructed and existing buildings. Although every effort is made to ensure the accuracy, currency and completeness of the information, the bulletin publishers and authors do not guarantee, warrant, represent or undertake that the information provided is correct, accurate or current and shall not be liable for any loss, claim, or demand arising directly or indirectly from any use or reliance upon the bulletin information. Bulletin reproduction in whole or in part is prohibited without the written consent of Firepoint Inc. Copyright 2021 – All Rights Reserved. See www.firepoint.ca or call 905-874-9400