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Insights Category: Technical Information

What is a dry pipe sprinkler system and where are they used?

Dry pipe systems are very similar to a wet pipe system. Instead of the pipes being filled with water, they are filled with pressurized air or nitrogen. Once the system is activated, the air is released, water travels through the pipes and is released out of the sprinkler heads that have been activated over the fire area.

A dry pipe system is typically installed in spaces that are subjected to temperatures below 40°F, such as parking garages, loading docks, or freezers. Areas like these that are exposed to low temperatures that can cause damage to water filled sprinkler.

Design challenges of dry pipe systems

While dry pipe systems are great for freeze protection, they do have some constraints that make their design a bit more difficult in areas where the water supply may be limited. For example, NFPA 13 §11.2.3.2.5 (2013 edition) states that the area of operation for dry pipe systems must be increased by 30% without revising the density. The reason behind this increase to the area is because there is a delay from when the sprinklers are activated to when the water reaches the fire. Wet pipe systems do not face this delay since the pipes are filled with water. Dry pipe systems, have to release the pressurized air or nitrogen before water is discharged, causing water delivery delays upon sprinkler head activation. During this delay, the fire will increase in size, thus triggering the need for a larger design area.

While an increased area of operation may seem like added protection, there are a few reasons why this can be troublesome for a system designer. An increase in area means more sprinklers are required to operate in order to provide the necessary amount of water over the design area.

Let’s look at a basic example of a parking garage with a dry pipe system:

  • Hazard Classification: Ordinary Group 1
  • Density/Area: 0.15(gpm/sqft) / 1500(sqft): 225 gpm
  • Adjusted Density/Area: 0.15(gpm/sqft) / 1950(sqft): 293 gpm

This example would require at least 293 gpm to be applied over the design area, not including hose allowance or extra flow from heads being fed at a higher pressure. If a wet pipe system was able to be used, the area could have been maintained at 1500 sqft, with only 225 gpm being required. This may not seem like a tremendous difference but when a building’s available water supply is limited, a designer will try and utilize any possible alternatives to get the systems to work without needing to modify the existing water supply. What are the other options to a dry pipe system?

Alternative options

NFPA 13 §8.16.4.1.1 states that any portion of a sprinkler system subjected to freezing or cannot maintain temperatures above 40°F shall be installed as a dry pipe system or preaction system. Much like a dry pipe system, a preaction system is faced with the same design challenges such as an increased design area. For locations with inadequate water supplies, these two systems may not be feasible so alternative options may be needed.

One option would be to provide a listed antifreeze system. An antifreeze system is similar to a wet pipe system in terms of liquid-filled piping but instead of water, the pipes are filled with a mix of water and antifreeze solution. This mixture prevents the pipes from freezing when the temperatures drop towards freezing conditions. An antifreeze system requires special considerations when preforming hydraulic calculations, as the mixture has different friction loss characteristics when compared to water. Additional components must also be used, such as a backflow preventer between the antifreeze system and the remainder of the system (to prevent any of the solution to contaminate the water supply) and an expansion chamber (to compensate for thermal expansion of the antifreeze solution). An additional challenge in the use of antifreeze systems is that antifreeze products listed for fire protection use are required.

Heat-tracing is another method that can be used. This method is ideal for sections of wet pipe that run through unheated areas, rather than entire systems. Heat tracing is an electronic tape or coil that is typically wrapped around a pipe and energized to maintain a preset temperature above freezing. If heat tracing is used on fire protection piping, then it must be supervised by the building’s fire alarm system and must send out a supervisory signal if the heat tracing system experiences any type of failure.

If additional systems such as heat tracing or antifreeze are not desired, then one of the simpler options for freeze protection would be to heat the space. This can be achieved by providing adequate insulation around the pipes or walls of the space. One example where this may be a good alternative would be in an attic. If an attic is unheated, then wet sprinkler pipe cannot be run through the space. However, if the pipe is within conditioned space by having the attic insulation above it, or the space itself is insulated, then a wet system can be used there. Providing insulation and heat for a space may not be ideal for an owner but if protection is required and a location cannot support a dry pipe system, adding the heat and insulation may be the better option.

Lastly, another option is a dry sprinkler head. These sprinklers are typically a “normal” sprinkler head that are on a section of pipe that remains dry, even though it is connected to a wet sprinkler system. This allows the branch line to be in a heated space, while the dry sprinkler extends through a wall or ceiling into the non-heated space. These are commonly used in walk-in coolers, underneath outdoor overhangs, or in unheated vestibules where conditioned space is close by.

These are some alternatives to dry pipe system. Each option has its pros and cons, and not all may be suitable for every situation. When deciding which option to use to protect an area subject to freezing, it is important to consider all factors. Sometimes the long-term cost associated with certain alternatives may outweigh the benefits.

If you have questions on what type of sprinkler system is needed for an area, or alternatives to dry sprinkler protection, please contact our office at info@crcfire.com.

Requirements for standpipe systems are found in Section 905 of 780 CMR Massachusetts State Building Code (9th edition), including various triggers for when a standpipe system is required for a building.  Within 780 CMR §905 and NFPA 14, Standard for the Installation of Standpipe and Hose Systems, three classes of standpipe systems are identified which vary based on the type of hose connections (aka fire department valves, hose valve) and/or hose stations required, the locations thereof, and the intended uses during a fire event. These three classes are differentiated as follows:

Historically, many buildings were required to have 1½-in. hose stations (i.e., Class II or Class III standpipe systems) intended for use by building occupants during a fire event. As automatic sprinkler systems became more commonplace, the fire protection industry and fire service generally shifted towards reliance on sprinkler systems applying water during the initial stages of a fire event – before arrival of the responding fire department – in favor of evacuating the building occupants to safety in a more timely fashion.  As a result, 780 CMR §905 includes several exceptions that allow installation of only a Class I standpipe systems in many cases, and a majority of buildings being designed and constructed under today’s code are permitted to only include 2½-in. hose connections. These classes of standpipe systems in 780 CMR are consistent with NFPA 14 Standard for the Installation of Standpipe & Hose Systems, the reference standard applicable to the design and installation of standpipes.

In addition to the three classes of standpipe systems, there are also different types of standpipe systems, each with their own design methodology in NFPA 14.  These include automatic wet, automatic dry, manual wet, manual dry, and semiautomatic dry which are generally described as follows:

In some cases, 780 CMR §905 identifies a specific class and type of standpipe system for a given condition, while in other cases, 780 CMR §905 only identifies the required class of standpipe system.  Where 780 CMR §905 is silent on the type of standpipe system, the Registered Design Professional has the option to select the suitable type of standpipe system based on factors such as the building height, occupancy type, available water supply, responding fire department capabilities, temperature conditions, etc., and provided that the installation complies with the applicable provisions of 780 CMR and NFPA 14 for the class and type of standpipe system selected. However, given that the standpipe systems are primarily intended for use by responding fire department personnel during a fire event, it is always encouraged to engage the local fire department to ensure that both the class and type of standpipe system being utilized aligns with their specific emergency response protocols, capabilities, and preferences.

For more information on the types of standpipes systems please contact us at info@crcfire.com

During firefighting operations in buildings protected by sprinkler and/or standpipe systems, the ability of the local fire department to appropriately supply these systems depends on proper signage being provided at the buildings fire department connections. It is the responsibility of the system designer to specify system information during design and installation due to their understanding of the layout and intent of the system(s) operation. This signage then becomes the responsibility of the property owner to maintain for the life of the building.

When specifying the appropriate signage for the building’s fire department connection(s), the two most important factors to consider are; 1) what the fire department connection is supplying, and 2) the location of the area being served.

The International Building Code (IBC), NFPA 13: Standard for the Installation of Sprinkler Systems, and NFPA 14: Standard for the Installation of Standpipe and Hose Systems, all require signage be provided at the fire department connection identifying the type of system being supplied (e.g., “Auto Sprinkler,” “Dry Standpipe,” “Sprinkler and Standpipe,” etc.) on permanently affixed, weatherproof placards. Where multiple fire department connections feed different zones or systems, each fire department connection needs to identify the system(s) or area(s) served. Clear, appropriately maintained signage by the property owner will enhance the fire department’s ability to supplement the sprinkler or standpipe system rapidly and reliably during building emergencies.

In addition, the pressure required to adequately supply the respective system needs to be identified such that fire department operations can occur effectively. NFPA 13 further outlines that the pressure required to adequately operate the fire department connection be indicated on the signage unless that pressure is 150 psi or less. This 150 psi is a critical number as NFPA 13E: Recommended Practice for Fire Department Operations in Properties Protected by Sprinkler and Standpipe Systems provides guidance to the local fire department as to how to operate sprinkler and standpipe systems effectively, recommends systems be supplied at 150 psi. Where the pressure necessary to serve the systems exceeds 150 psi, the systems’ pressure needs to be included on the signage to allow the pump operator to supply the system effectively.

For more information on fire department connection signage please contact us at info@crcfire.com

As of July 1, 2021, the Joint Commission’s new life safety chapter covering business occupancies went into effect.

Accredited facilities can now be surveyed within business occupancies for compliance with the Joint Commission life safety standards and NFPA 101, 2012 Edition. One of the key differences between the requirements for a healthcare occupancy and a business or ambulatory care occupancy is the protection of hazardous areas. Designers and facility managers alike should be made aware that the requirements differ based on the occupancy types, placing emphasis on the accuracy of life safety drawings for a facility on survey. Both ambulatory care and business occupancies contain the same requirements for separation of hazardous areas. Hazardous areas including but not limited to areas used for general storage, boiler or furnace rooms, and maintenance shops that include woodworking and painting areas are required to be protected with smoke partitions and doors that are self or automatic closing with latching hardware in a room or space that is fully sprinkler protected (NFPA 101 38/39.3.2, 8.7, 8.4). Note that these separations may be less restrictive than the 1-hour separations required for soiled linen rooms and storage rooms over 100 square feet in new healthcare occupancies in Section 18.3.2. The analysis of what amount of general storage of combustible warrants a hazard is a subjective analysis performed by the authority having jurisdiction (AHJ).

If you have any questions or would like assistance with determining the best approach for the design of your hazardous storage rooms, please do not hesitate to contact us at info@crcfire.com

Mass Timber (MT) construction, including Cross-Laminated Timber (CLT) and glue-laminated (glulam) structural members, are growing in popularity, with advances in assembly fire testing and code requirements furthering fire and life safety compliance options.

Where a CLT or glulam element is required to carry a fire-resistance rating (FRR), there are two general options available: (1) comply with a tested or listed system, or (2) calculate the FRR using the “char depth” method.  For the latter option, a member is structurally over-sized to allow for a calculated portion of the member to be sacrificial, and burn and char if exposed to a fire event.  The charring creates a natural insulation for the remaining intact portion of the wood, allowing for structural integrity to be maintained for a certain period of time.

The use of the char depth calculation method is permitted through Section 722 of the 2015 IBC, which references Chapter 16, Fire Design of Wood Members, of the 2015 National Design Specification (NDS) for Wood Construction, with a commonly used and validated char rate at 1.5 – 1.8 inches/hour. If this option is pursued, it should be coordinated between the structural engineer of record and the fire/life safety consultant on the project.

In addition to the char depth calculation approach, tested systems are also available for use in such construction, with more and more becoming available each year. When using such test reports or listings, compliance with the details of the tested system should be reviewed for application into the design.

We have been involved in several mass timber projects and are looking forward to seeing more of this building method in the future! If you have any question on Mass Timber in construction, please reach out to our office at  info@crcfire.com to find out how we can assist.

Click the links below to view the other Insights in the Mass Timber series:

Mass Timber – Concealed Spaces

Mass Timber – Exposed Wood in Type IV-B Construction

 

The Massachusetts State Building Code (780 CMR 9th Edition) provides two main design methodologies for public parking garages, either “open” or “enclosed”.  Developers and design teams can capitalize on several advantages when designing parking garages as an “open parking structure” versus an “enclosed parking structure”, with the most prevalent being the cost savings associated with the omission of mechanical ventilation & sprinkler systems. These advantages, along with several other notable ones, are further detailed below:

  • Sprinkler System Omission: In general, where open parking garages are constructed as standalone structures or separated from other portions of mixed-used development by a firewall (i.e. Texas Wrap Configuration), sprinkler protection of the parking garage is not required when meeting the openness criteria in 780 CMR Section 406.5.2 and Mass General Law Section 26G.
  • Height and Area Increases: Significant increases in the allowable height and area are permitted for single-use open parking garages. This in turn allows for less restrictive construction types and reduction in the required fire-resistance rating of building elements.
  • Fire Separation Distance: Open parking garages having a fire separation distance of 10 feet or more are permitted to have unlimited unprotected openings, regardless of its construction type (780 CMR Table 602 Note C).
  • Exit Stair Openness: Stairways serving open parking garages are not required to be enclosed in fire-resistance rated shaft construction (780 CMR 406.5.9, 1019.3(6)). Even though stairways are not required to be enclosed, the exit access travel distance from each tier is permitted to terminate at the closet riser of the stair (780 CMR 1017.3(1)).
  • Mechanical System Omission: Mechanical exhaust or supply duct systems serving only open parking garages are not required to be enclosed in fire-resistance rated construction (780 CMR 712.1.10.3).

To utilize the above advantages, there are certain fire protection and life safety considerations that architects, owners, and developers should be aware of when designing open parking garages in accordance with 780 CMR Section 406.5:

  • Single use: In order to apply the height and area increases for open parking garages (in lieu of the normal height and area limits in IBC chapter 5), the structure must be used exclusively for the parking or storage of private motor vehicles. No other uses in the building are permitted with the exception to offices, waiting rooms, and toilet facilities having a combined area of 1,000 sf at the grade level tier.
  • Omission of Automatic Sprinkler System: Below are critical design features to note where sprinkler systems are omitted from the open parking garage:
    • Mass General Law Section 26G requires non-sprinklered open parking garages to have a net free area of at least 25% of the total perimeter wall area of each tier, a 5% increase from the base provisions in the IBC.
    • Stairways serving as a required accessible means of egress must have a minimum 48” minimum clear width between handrails (780 CMR 1009.3).
    • Fire department vehicle access roads must be designed to extend within 150 feet of all portions of the exterior wall on the first story. This distance is increased to 250 feet for fully sprinklered buildings (527 CMR 18.2.3.2.2).
  • Decorative Screens: The net free area of openings must be utilized for the purposes of achieving natural ventilation. As decorative screens have become desirable and popular for covering openings of parking garages, the resulting impact to the garage’s natural ventilation openings must be considered, to ensure that the new effective free area remains above the required percentage.

There are certainly several cost benefits of designing public parking garages as “open” versus “enclosed”, however, it is critical for developers and design teams to consider all building and fire protection design features associated with the advantages of open parking garages in order to maintain compliance with 780 CMR and Mass General Law.

If you have questions on open parking garage features, please reach out to our office at info@crcfire.com to find out how we can assist.

As discussed in Code Red Consultant’s prior Insights on fire department access, roadway dimensional criteria, proximity to buildings as well as materials and maintenance of the roadways are critical to the design and longevity of a project to ensure responding apparatus can access a site.  This week’s blog will address the impacts of traffic calming devices to fire department access.

Traffic calming devices are commonly used when the traffic pattern of a particular area is not conducive to the nearby residential, recreational, or retail land uses. These devices are designed to reduce speed, increase driver focus, and in some cases encourage drivers to seek alternative routes, to enhance pedestrian, cyclist, and local traffic safety. Traffic calming devices can include the following measures:

  • Narrowing of roadways, such as reducing lane width, allowing on street parking, or converting one-lane roadways to two-lane roadways. These measures ensure that slower speeds and more attentive driving is necessary.
  • Vertical deflection, such as speed humps, speed bumps, speed tables, rumble strips, and raised pedestrian walkways. These deflections cause discomfort for drivers, and can cause damage to larger vehicles if traveling at significant speeds.
  • Horizontal deflection, such as chicanes. These deflections require drivers to swerve slightly, promoting more attentive and slower driving.

The major drawback to implementing traffic calming devices relates to first responder access. The primary concerns of the response community are timely arrival to an incident scene, with all emergency vehicle occupants arriving safely. Devices or strategies designed to slow the speed of traffic can greatly reduce response time, and can even cause damage to larger vehicles such as fire engines and ladder trucks. A 1995 study by the Portland, Oregon Bureau of Fire, Rescue, and Emergency Services tested the response times for 6 different sized fire vehicles at a various response speeds vs. common traffic calming devices (https://nacto.org/wp-content/uploads/2012/06/City-of-Portland-1996.pdf ). The study produced the following range of delays:

  • 14-foot speed bumps: 1.0 to 9.4 seconds of delay per bump
  • 22-foot speed bumps: 0.0 to 9.2 seconds of delay per bump
  • Traffic Circle: 1.3 to 10.7 seconds of delay per circle

NFPA 1141, Standard for Fire Protection Infrastructure for Land Development in Wildland, Rural, and Suburban Areas outlines requirements for traffic calming in relation to fire department access. Section A.5.2.18 states that “prior to installation of traffic calming, the authority having jurisdiction should work with the emergency response department(s) to ensure traffic calming devices can be negotiated by emergency response vehicles in a safe and timely manner without damage to those vehicles”. This requirement is echoed in 527 CMR 1.00, requiring AHJ approval for any traffic calming devices.

In response to the negative impact on first responder access, new traffic calming devices have been developed with easier passage for emergency vehicles in mind. These include speed tables and speed humps with gaps that line up with fire engine tire width.

While devices like these exist, it is important to ensure that coordination with the local emergency response agencies is paramount. Being cognizant of the needs, operating procedures, and equipment of the local fire department will ensure that a strategy is implemented that both increases pedestrian safety from traffic but also ensures little to no impact on response times of first responders.

This completes are blog series on fire department access.  We hope you found the content informative and will consider it a resource for future project planning. If you have questions on fire department access compliance, please reach out to our office at info@crcfire.com to find out how we can assist.

Click the links below to view the other Insights in the FD Access series:

Introduction

Part 1 Roadway Dimensions

Part 2 Roadway Materials and Maintenance

Part 3 Proximity to Buildings

As discussed in Code Red Consultant’s prior Insights on fire department access, roadway dimensional criteria as well as materials and maintenance are critical to the design and longevity of a project to ensure responding apparatus can access a site.  This week’s blog will focus on the proximity of fire department access roads to the building itself as required by 527 CMR 1.00:  Massachusetts Comprehensive Fire Safety Code.

Fire department access roads are required to be provided for every facility, building, or portion thereof. The location of the fire department access road relative to the building is required to comply with 527 CMR 18.2.3.2. The specific requirements for fire department access roads are as follows:

  • It shall extend to within 50 feet of at least one exterior door that can be opened from the outside and that provides access to the interior of the building;
  • Is required to extend to within 150 feet of all portions of the exterior wall of the building, or 250 feet where the building is provided with an NFPA 13 sprinkler system (note that NFPA 13D and NFPA 13R systems cannot be used to satisfy this requirement);
  • Dead end access roads in excess of 150 feet are required to be provided with an appropriate turning radius or T-turn. All fire department access road requirements are required to be provided for the turning areas (13’-6” height, 20’ width)

It is recommended that all fire department access roads are reviewed with the local fire department.

Our next post will focus on traffic calming devices relative to fire department access.  If you have questions on fire department access compliance, please reach out to our office at info@crcfire.com to find out how we can assist.

Click the links below to view the other Insights in the FD Access series:

Introduction

Part 1 Roadway Dimensions

Part 2 Roadway Materials and Maintenance

Part 4 Traffic Calming Devices

As discussed in Code Red’s prior Insights on fire department access, roadway dimensional criteria are critical to the design of a project to ensure responding apparatus can access a site.  This blog will review the material and maintenance criteria of these roadways as outlined in 527 CMR 1.00:  Massachusetts Comprehensive Fire Safety Code.  How does this apply to the design and lifetime maintenance of the roadway?

In designing fire department access roads, it is important to consider any existing buried structures such as culverts, pipes, electrical duct banks, and even septic tanks. It is important to ask yourself, can these structures support the significant weight of a fire apparatus? Weather conditions such as heavy rainfall or freezing temperatures can quickly change the drivability of the road and will have an impact on the materials used to construct the roadway. For example, if a road, located in a valley that has historically flooded in heavy storms, is to be designed as a fire department access road, selecting dirt as the finish surface material will likely result in the road’s inability to support a fire department vehicle when the dirt’s load bearing capability is reduced in a storm. A material such as asphalt with sufficient thickness of material below the surface will be better at maintaining its load bearing capabilities.

During the design of fire department access roadways, the loads imposed by jacks, outriggers, and stabilizers for aerial ladder trucks is often overlooked. These stabilizers are designed to be capable of supporting the full load of the vehicle, which will result in the weight of the vehicle becoming concentrated on the jacks or outriggers. For example, a gravel road may be capable of supporting a fire department vehicle traveling on ten tires, however, when the aerial ladder and associated stabilizers are needed, the gravel may not be capable of supporting the concentrated load of the stabilizers. This can put the ladder truck at risk of sinking into the ground or tipping over.

The maintenance over the life of the roadway should also be considered during the of fire department access roadway. For example, selecting permeable pavers with grass as the top surface of the roadway might be advantageous from an aesthetic perspective, and may even be capable of supporting the load of a fire department vehicle. However, during the winter months when snowfall occurs, the pavers are difficult to plow. If the plow is set too high off the ground, it will leave residual packed snow that will turn to ice and create a hazard to the responding fire apparatus – and anyone else using the roadway. If the plow is set too low, it can rip up the pavers and grass and require repair. The same grass roadways can also blend into the adjacent grass during the summer months, creating visual difficulties for the responding fire department personnel to locate the boundaries of the road.

Regardless of the road surface, fire department access roads must be maintained as drivable throughout the life of the building. All road surfaces – concrete, asphalt, gravel, and even crushed clam shells – require ongoing maintenance. Excessive cracking or ruts can indicate failure of the subgrade, and annual freeze-thaw cycles can cause potholes, frost heaves, and other damage that can prevent a fire engine from using the roadway.

While the design and maintenance of fire department access roads only comprises a few short sections in 527 CMR 1.00, there are large implications for the project that can result from not providing access in an approved way. Careful planning and an open discussion with the fire official can mitigate many of the challenges that fire department access roadways can bring.

Our next post will focus on the proximity of the fire department access road to a building.  If you have questions on fire department access compliance, please reach out to our office at info@crcfire.com to find out how we can assist.

Click the links below to view the other Insights in the FD Access series:

Introduction

Part 1 Roadway Dimensions

Part 3 Proximity to Buildings

Part 4 Traffic Calming Devices

Throughout October, we will be providing Insights on fire department access through a series of blog posts in celebration of Fire Prevention Week 2021. While the Massachusetts State Building Code is silent on fire department access, the Massachusetts Comprehensive Fire Safety Code (527 CMR 1.00), contains the requirements for fire department access, and is enforced by the local fire department. In this Insight, we will discuss the minimum dimensional criteria for fire department access roads.

Fire department access roads are required to have an unobstructed width of not less than 20 feet, and a vertical clearance of not less than 13 feet 6 inches. This width is required to be maintained at all times, and cannot be obstructed by parked cars, curbs, and snow piles during the winter months of New England. The vertical clearance also cannot be reduced by items such as trees, bridges, walkways, power lines, decorative catenary lighting, and building overhangs.

These requirements take into account the need for fire apparatuses to pass each other, compartment doors to open, and the additional width required for ladder trucks to deploy jacks or outriggers. Vertical clearance is needed not only for the height of the trucks, but also to allow for access of equipment that is stored on top of trucks.

Fire department access roads are also required to have a minimum inside turning radius of at least 25 feet unless otherwise required by the fire official. This generally provides adequate space for the long wheelbase of fire apparatus to make a turn. The outside turning radius is required to be at least 45 feet (25 feet for the inside turning radius and 20 feet for the access road width). Keep in mind that the fire department can require a larger turning radius.  Some fire apparatuses, particularly tower ladders, can have an outside turning radius (“wall-to-wall” turning radius) close to 50 feet – giving an overall turning circle of 100 feet or more.

Although a fire department access road is defined as the road or other means developed to allow access and operational setup for firefighting and rescue apparatus, the fire department has been known to use any means that is necessary to get to a building during an emergency. That said, providing properly sized and capable roadways can ensure that damage to landscaping or roadways – and to fire apparatus – does not occur during an incident. This is why it is so important to understand and maintain the fire department access road requirements on any project.

Our next post will focus on the design and maintenance of fire department access roads.

If you have questions on fire department access, contact our office at info@crcfire.com

Click the links below to view the other Insights in the FD Access series:

Introduction

Part 2 Roadway Materials and Maintenance

Part 3 Proximity to Buildings

Part 4 Traffic Calming Devices