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#68 -- Fire Sprinkler Riser: Components and Benefits for Sprinkler Contractors

Posted by Jason Hugo and Anna Hartenbach on 7/20/2017 to Fire Sprinkler System Components
As more jurisdictions join the ranks of those that require fire sprinkler systems, industry professionals are continuously seeking innovative solutions to make sprinkler system design and installation faster and cheaper. While fire sprinkler system installation is a lengthy process, one of the more time-consuming steps is the fabrication and assembly of the system’s riser, which was traditionally built from scratch.

With the introduction of pre-assembled commercial and residential riser manifests, this step in the process can now be standardized and sped up considerably. Keep reading to learn more!

In this article, we’re going to look at Residential and Commercial Risers for a more in-depth understanding. We’ll look at the benefits associated with their use and figure out what you should look for when selecting a riser assembly.

Already know what riser solution you need for your next fire sprinkler system job? Jump straight to our selection of residential and commercial risers.

What are the benefits of commercial and residential riser?

Before the ease of pre-built riser manifolds, the installation of fire sprinklers was synonymous with the word “more.” That’s because it took more of everything: more supplies, more thought, more planning, more energy, more people, more labor, and, definitely more time.

Since riser manifolds were commonly built from scratch, there were more necessary parts required for assembly and, therefore, more parts to account for when ordering supplies. These systems required more thought and planning since pipes had to be cut to size and specification to build the manifold, meet the needs of the system, and comply with code. Not to mention they were complicated and awkward to install due to their size and weight, which required more people.

So why buy a pre-built riser manifold in lieu of building one yourself?

As a contractor, the main benefit of commercial or residential risers is the time saved in buying and assembling the individual pieces. Complete riser kits are compact and lightweight, allowing for easier installation. Not to mention the money and labor you save by reducing the amount of time and number of people required for assembly. Furthermore, because they’re manufactured as one piece it’s easier to be consistent and code-compliant in facilities and dwellings that require more than one riser manifold.

Now, factory-assembled riser manifolds are readily available in a variety of makes and configurations, making it easier than ever to get the best fit for your system with little time and effort on your part. In addition to meeting the needs of each type of fire sprinkler system, these manifolds meet the requirements of local, state, and national code.

Who doesn’t want to save time, energy, and money?

The overarching theme in transitioning from “more” to “less” is a more cost-efficient, economical fire sprinkler system. In turn, this allows your company to offer more reasonably priced systems to your customers and/or increase your profits.

What components make up fire sprinkler riser manifolds?

Generally, the specific components needed for your riser manifold depends on the type of sprinkler system and how it’s being assembled. With that being said, both the Residential and Commercial Risers are made with a pressure gauge, flow switch, and the appropriate drain valve to meet the system’s requirements within NFPA 13, 13D, and 13R.

Residential Riser Assembly
Residential Riser Components

The simplest and most commonly used sprinkler system is a Wet System. It draws water from a dependable source and utilizes pressure to push it through the system and out the sprinkler heads1. The riser acts as the bridge to “rise” the water supply to the sprinklers in the event of an emergency. Selecting the appropriate components ensures the system will function properly.

The biggest differentiating factor in Commercial and Residential Risers is the type of drain valve used on the manifold and the option for a pressure relief valve. Most Commercial and Residential Risers are offered with three drain valve options: a ball valve, a Test and Drain valve, or either of the aforementioned valves in combination with a Pressure Relief Valve.

Commercial Riser Assembly
Commercial Riser Assembly

In most instances, determining the necessary components comes down to the specific requirements of the system being built and compliance with NFPA 13.

Pressure Gauges

In any commercial or residential riser assembly built with a check valve, a pressure gauge must be installed. They should be installed above and below each alarm check valve or system riser check valve, when they are used.

From the 2016 Edition of NFPA 13:

7.1.1.1An approved pressure gauge conforming to 8.17.3 shall be installed in each system riser.
7.1.1.2 Pressure gauges shall be installed above and below each alarm check valve or system riser check valve where such devices are present.
7.1.1.2.1 Pressure gauges below check valves required by 8.17.5.2.2(1) shall not be required.

Valves - Ball Valve or Test and Drain

Ball valves are included on the most basic models of commercial and residential risers. They allow the system to be drained. Where a ball valve is used, testing is performed with an Inspector’s Test and sight glass at the end of line. This method requires the system to be depressurized and drained through a main drain prior to testing.

Test and Drain valves are an alternative option to ball valves. The major differentiating factor is that a Test and Drain provides the ability to perform hydrostatic testing, in accordance with NFPA 25, on the sprinkler system without draining it first because it has a sight glass for water observation and a testing orifice that simulates a 5.6k sprinkler discharge (more on this later)1. Therefore, it provides an elegant solution for the need to test the system.

From the 2016 Edition of NFPA 13:

6.6.1.1 Valve Pressure Requirements. When water pressure exceeds 175 psi (12 bar), valves shall be used in accordance with their pressure ratings.
6.6.1.2Valve Closure Time. Listed indicating valves shall not close in less than 5 seconds when operated a maximum possible speed from the fully open position.
6.6.3Drain Valves and Test Valves. Drain valves and test valves shall be approved.
6.6.4.1All control, drain, venting, and test connection valves shall be provided with permanently marked weatherproof metal or rigid plastic identification signs.
6.6.4.2The identification sign shall be secured with corrosion resistant wire, chain, or other approved means.

Though both valve types are approved for use on a fire sprinkler system and riser assembly, there are benefits to both, which we’ll cover more. The important takeaway is that whichever valve is used, it must perform in accordance with the pressure ratings of the sprinkler system, it shall not close in less than 5 seconds, and they must be properly identified.

Waterflow Detection Alarm

In a Wet Pipe System, the NFPA requires a waterflow detector, or flow switch, connected to an alarm. The are designed to initiate the alarm when the sprinkler system is activated. Because sprinkler systems are automatic, water flow devices can be made to signal an alarm system connected to the sprinkler system (e.g., a bell, water motor gong, or electronic horns).

From the 2016 Edition of NFPA 13:

6.8.2.1 Wet Pipe Systems. The alarm apparatus for a wet pipe system shall consist of a listed alarm check valve or other listed waterflow detection alarm device with the necessary attachments required to give an alarm.

To explain the importance of the waterflow detector, we need to describe the alarm check valve, which occurs prior to the riser within the sprinkler system. These valves are used to prevent water within the system, which is no longer considered potable, from flowing back into the water supply. Within the alarm check valve is a spring, valve clapper, and alarm port. It’s the spring’s job to hold valve clapper closed and ensure the water only flows in one direction. In the event of a fire emergency, as the temperature rises and activates a fire sprinkler, the clapper opens so water can flow, triggering the flow of water through the system. The pressure on the alarm port, from the water moving through the system, prompts the water motor gong, mechanical bell, or A/V device to sound. Now, waterflow detectors are most commonly used in place of the mechanical water motor gong. Waterflow detectors can be connected to an electric bell, horn, or horn/strobe and they function similarly to the water motor gong, in that the pressure on the alarm port where an alarm pressure switch can be installed, which will trip the alarm signal to the panel2.

Pressure Relief Valve

A pressure relief valve is required in all wet pipe systems unless they are built with auxiliary air reservoirs to absorb pressure increases. That being said, the relief valve cannot be less than ½ in (15 mm) in size and must operate at 175 psi (12 bar) or 10 psi (0.7 bar), not exceeding the system’s maximum pressure rating. Relief valves are positioned downstream of check valves3.

From the 2016 Edition of NFPA 13:
7.1.2.1Unless the requirements of 7.1.2.2 are met, a wet pipe system shall be provided with a listed relief valve not less than ½ in. (15 mm) in size and set to operate at 175 psi (12 bar) or 10 psi (0.7 bar) in excess of the maximum system pressure, whichever is greater.
7.1.2.2Where auxiliary air reservoirs are installed to absorb pressure increases, a relief valve shall not be required.
7.1.2.3A relief valve per 7.1.2.1 shall be required downstream of check valves required by 8.17.5.2.2(1).
8.16.1.2.3*A listed relief valve of not less than ½ in. (15 mm) in size shall be provided on the discharge side of the pressure-reducing valve set to operate at a pressure not exceeding the rated pressure of the components of the system.
A.8.16.1.2.3 Where the relief valve operations would result in water being discharged onto interior walking or working surfaces, consideration should be given to piping the discharge from the valve to a drain connection or other safe location.

In a nutshell, most wet pipe systems need some form of pressure relief – whether that be by way of a Pressure Relief Valve or auxiliary air reservoirs. Otherwise, the pressure within the system can build and exceed the pressure rating of the various fire sprinkler system components.

What are Common Pre-Assembled Riser Manifold Configurations?

Commercial and residential risers, in and of themselves, are beneficial because they come pre-assembled and pressure-tested to meet NFPA 13, 13D, and 13R. Because they come with all required equipment, there is no more guesswork involved with ordering the correct parts and assembling them in the field. However, it should be noted that each component can be easily replaced in the field, if necessary.

Basic Trim – This riser manifold configuration is aptly named, as it’s the most basic model of the three configurations. Like all riser assemblies we’re discussing today, the riser with basic trim allows the system to be drained. However, it doesn’t enable testing at the riser, it must be done at the end of the line with an Inspector’s Test and sight glass. The riser with basic trim is acceptable for use in a system where pressure increases are absorbed through installed auxiliary air reservoirs.

Test and Drain – Commercial or Residential Risers equipped with a Test and Drain have an advantage over the Basic Trim model – the ability to perform hydrostatic testing without draining the system. With this trim package, the Test and Drain enables easy system draining similar to the ball valve. However, the Test and Drain also includes a sight glass so the flow of water can be observed without witnessing flow from the exterior of the building. The built in ½” testing orifice simulates the flow of a sprinkler head to facilitate testing and produce accurate results, ensuring the alarm will trigger and the system will function properly in the event of an emergency. Furthermore, it eliminates instances where the Inspector’s Test would be easily accessible to the public (ex. in stairwells, etc.) and tampered with, potentially triggering false alarms.

Pressure Relief Valve (PRV) – In compliance with NFPA 13, a relief valve is a requirement for gridded systems or others requiring a pressure relieve valve. Gridded sprinkler systems are those that have parallel cross mains, which have many branch lines to ensure that a sprinkler head receives water in both directions. Temperature changes or gravity can cause pressure to build within the sprinkler system above recommended levels since wet systems are closed systems with nowhere for the pressure to go. Therefore, a pressure relief valve or auxiliary air reservoir is necessary. The pressure relief valve slowly releases that pressure on-demand, so the system remains in compliance.

Why choose QRFS?

At QRFS we offer Residential and Commercial Risers in a variety of configurations to meet your sprinkler system specifications. Our riser kits are in stock, are fully UL and FM compliant, and, as previously discussed, will save you both time and money compared to traditional riser construction and installation.

We stock both Residential and Commercial risers. For residential, we offer a great line of Residential Risers with Basic Trim, Basic Trim with Test and Drain, and Basic Trim with Pressure Relief Kit. All three configurations have a working pressure of 175 PSI and parts are UL listed. In addition, we offer Commercial Risers with your choice of a Test and Drain or ball valve.

In addition, at QRFS we take the time to educate ourselves in NFPA Code and industry best practices so we can assist you in selecting the right product to fit your project. We want to be your partner, delivering the right best-in-class fire protection equipment on-time. QRFS is the best of both worlds: we offer the selection of a traditional distributor with the cost-advantages and ease-of-use of an eCommerce marketplace. So take advantage of the best of both worlds today and order your next Riser Manifold from QRFS.com!






Still have questions? Comment below and we’ll reply as quickly as possible to get your project on the right track.

This blog was originally posted by Jason Hugo and Anna Hartenbach at QRFS.com/blog on July 14, 2017. If you found this article useful, check us out at Facebook.com/QuickResponseFireSupply or on Twitter @QuickResponseFS.

Sources:
  1. Wet System Manual: Viking. Technical Manual for Operation, Maintenance, and Troubleshooting.
  2. Applications Guide: Fire Sprinkler Systems Monitoring, System Sensor.
  3. AGF Sell Sheet: Pressure Relief Valves.

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