There is no doubt that the trend towards the use of synthetic fluorine-free foams (SFFF) in fixed fire-protection systems is gathering pace. The conversation is no longer if, or even when, it is simply that the market needs a solution now.
Unfortunately, these solutions are not coming to market quickly enough to meet legislative and environmental demand and any hope of ‘drop-in replacements’ is beyond reality for now. A particular area of concern is the availability of suitable SFFF products for use in conventional sprinkler systems.
So, what is the problem?
Fire-protection sprinklers and sprinkler nozzles are a simple but effective form of active fire protection used in many different applications globally. They are deployed in closed-head systems with a fusible element or as sprinkler nozzles in open deluge systems with the fusible element removed. For many years, we have been enhancing these systems with foam to tackle more challenging fire scenarios such as those posed by Class B ignitable liquids. Typical applications are refineries, aircraft hangars, manufacturing and logistics centres with ignitable liquids and other commodities, where water alone is less/ineffective. Conventional fire sprinklers were not designed with foam use in mind. They are designed to efficiently distribute water in the desired manner depending on the object or risk they are protecting. They are also small, discreet and, due to the high volume used throughout the world, have a sensitive, almost commodity-based price point. Despite this, when used with the correct combination of system components and foam concentrate, they can perform very well as foam-enhanced sprinkler systems.
Why is a sprinkler different?
A conventional fire sprinkler is considered a non-aspirated foam discharge device and typically gives a low expansion ratio of no more than 4:1, with fast drainage times. It is therefore important to select a foam concentrate that has been developed and independently tested by a third party specifically for use with sprinklers. Factory Mutual (FM) and Underwriters Laboratories (UL) are considered the most relevant and challenging authorities when it comes to fixed-system product testing. Their respective foam test standards, FM5130 and UL162 include material testing, fire-performance testing and follow-up manufacturing audits, which gives a higher level of consumer confidence compared to other standards commonly referenced, such as Europe’s EN13565-1. Both these organisations recognise that conventional non-aspirated sprinklers are different in foam performance to other discharge devices and therefore, the traditional foam-quality approach is not applicable. Instead, each sprinkler type is tested under prescribed conditions with variables such as foam concentrate type, K-Factor, application density, fuel type and installation height.
The example sprinkler and foam concentrate approval in the table gives clear design and usage parameters from the fire testing.
Application design standards such as NFPA11, NFPA30 or FMDS 7-29 require the use of Approved/Listed foam concentrates that have been tested on the subject fuels with the intended sprinkler type. This can limit choice because such testing is difficult and expensive, but the user does at least have the assurance of proven fire performance.
Use of FM-Approved or UL-Listed foam concentrates tested with sprinklers is a sound approach to fire performance. Manufacturers using the freedom allowed under EN13565-2:2018 to justify the use of foams with non-aspirated sprinklers based on foam quality alone are not considering the full picture.
New advances in SFFF
We are in a phase when demand for Approved/Listed foam systems is moving faster than manufacturers can bring solutions to market. This situation is not due to complacency or lack of effort, it is because replacing fluorinated foam systems with non-fluorinated is challenging, time consuming and expensive. At the time of writing, there is a slow increase in the number of high-quality foams meeting some of the requirements of FM5130 and UL162 entering the market. Choices for foam concentrates with non-aspirated foam concentrates remain very small, however. An exciting new foam entered the market recently. This is Viking’s ARK product, which is developed in conjunction with a selection of Viking sprinklers and hardware. The Viking ARK foam concentrate is the very first SFFF foam concentrate to achieve FM Approval for use on hydrocarbon and polar solvent ignitable liquids. This achievement is the culmination of many years of work with a strict focus on non-aspirated sprinkler performance.
For certain applications, particularly warehouse storage, it is important to have a high-performing foam working with non-aspirated sprinklers as there can be thousands of these small, cost-effective foam discharge devices installed. As part of this FM system approval, there is a proportioning package comprising an extensive line of bladder tanks with wide-range proportioners specifically designed and approved for use in closed-head sprinkler systems where flow rates can be very low. This special proportioning device is able to manage the higher viscosities found with SFFF foams and comes with the assurance provided by test standards such as FM5130. Additional products, sizes and design parameters are added to the product line in the coming months.
For more information, go to www.viking-emea.com