Code Red Consultants

For projects in Massachusetts, interior and exterior signs identifying permanent rooms and spaces are required to comply with 521 CMR and the 2010 ADA.  521 CMR Section 41.2.2 states that the mounting height of permanent room signs is required to be 60” above the finish floor to the centerline of the sign.  Section 703.4.1 of the 2010 ADA requires tactile characters to be a minimum of 48” above the finish floor, measured from the baseline of the lowest tactile character, and 60” maximum from the finish floor, measured from the baseline of the highest tactile character.

In many cases, it is not possible to comply with both 521 CMR and ADA when mounting a sign.  In December 2021, the Massachusetts Architectural Access Board (MAAB) released an advisory opinion stating that the ADA signage mounting requirement provides equal or greater access compared to the 521 CMR requirement. Based on the advisory opinion, only the mounting height requirement of the ADA need to be considered without seeking a variance to 521 CMR.  The mounting height figure for signage as seen in chapter 703 of ADA is shown below:

This week’s Insights post discusses how a building’s Fire Separation Distance (FSD) and Frontage are measured from adjacent buildings or structures, lot lines, and public ways. There are various impacts that these measurements have, including the composition of the building’s exterior wall construction, restrictions on unprotected openings, and allowable building area, which are all critical to a building’s façade, geometry, and shape and size. Therefore, it is crucial to appreciate these attributes early in design. For the purposes of this post, the 2015 Edition of the International Building Code (IBC) is referenced as it is the currently adopted model code for the Massachusetts State Building Code (780 CMR).

The IBC defines Fire Separation Distance (FSD) as the distance measured from the building face (at a right angle from the face of the wall) to one of the following (IBC Section 202):

  • The closest interior lot line;
  • To the centerline of a street, alley, or public way;
  • Or, to an imaginary lot line between two buildings on the same lot (note: an imaginary lot line does not have to be equidistantly placed between two buildings)

A demonstration of each of these three conditions are shown in the figures below (IBC Commentary, Figure 202(20) – 202(22)):

Most notably, FSD drives the fire-resistance rating required for exterior walls based on occupancy type(s) and the construction type of the building (IBC Table 602). FSD also dictates the percentage of allowable unprotected openings that may be permitted in the exterior wall (IBC Table 705.8), in order to mitigate the potential of flame spread from one structure to an adjacent one.

Similar in concept to Fire Separation Distance (FSD), Frontage of a building is a measure of the amount of open space or access to a public way around a building’s perimeter. However, this factor drives allowable area increases for the building (IBC Section 506.3). The IBC Commentary expands on this concept to state that “the allowable area of a building is allowed to be increased when it has a certain amount of frontage on streets (public ways) or open spaces, since this provides access to the structure by fire service personnel, a temporary refuge area for occupants as the leave the building and reduces exposure to and from adjacent structures.

In order to qualify for Frontage Increase, a building must possess:

  • At least 25% of its perimeter located along a public way or open space (IBC Section 506.3.1);
  • At least 20 feet in width from the building’s exterior wall to the public way or open, as measured at right angles to any of the following (IBC Section 506.3.2):
  • The closest interior lot line;
  • The entire width of a street, alley, or public way;
  • Or the exterior face of an adjacent building on the same property.

An important distinction for a portion of the building’s perimeter to qualify for Frontage is the need for the wall to be accessible for the fire department by means of a street or fire lane. The IBC Commentary expands on fire department access with: “for instance, if the back side of a building on a narrow lot cannot be reached by means of a fire lane on one side of the building (and there is no alley or street at the back), that portion of the perimeter is not considered open for purposes of frontage increase, even if there is actual open space exceeding 20 feet in width.” For example, the north exterior wall in the figure below can be accounted for Frontage since a fire lane is provided on the adjacent side (IBC Commentary Figure 506.3.2.(1)).

Please note that the content of this blog is relative to a new building with respect to existing or known site conditions on its lot. This does not account for any requirements (in terms of fire-resistance rating or proximity from a building), for select equipment such as electrical transformers, emergency generators, chemical or gas bulk storage tanks, dumpsters, sheds, etc. Please refer to the codes and standards specific to these types of equipment or features for any additional separation requirements from adjacent structures.

For information or request for assistance on your project, please contact us at info@crcfire.com.

 

 

 

 

Laboratory Life Safety – NFPA 45 and Means of Egress

With the current influx of life science projects, a few questions are becoming increasingly common: Are there any specialty egress requirements for R&D laboratories? Are there any code considerations to be aware of regarding the layout of laboratory equipment? The answers to these questions tie back to the Laboratory Unit approach as regulated by NFPA 45, Standard on Fire Protection for Laboratories Using Chemicals (2011 edition).

What is a Laboratory Unit?

NFPA 45 utilizes the concept of Laboratory Units, which are similar in concept to control areas in that they are compartmentalized areas in which the allowable quantities of chemicals are limited. Laboratory Units are classified as Class A (high fire hazard), Class B (moderate fire hazard), Class C (low fire hazard), or Class D (minimal fire hazard) based on the quantities of flammable and combustible liquids within the unit. As the relative fire hazard increases, the requirements for life safety and means of egress become more stringent.

How many exits do I need to serve my Laboratory Unit?

NFPA 45 contains specific criteria for determining where a second means of access to an exit is required from a laboratory space, which may be more restrictive than the criteria otherwise specified by local building and life safety codes. The required egress arrangement will be dictated by the classification and size of the laboratory unit, as well as by the arrangement of equipment and hazards within the laboratory unit. For example, if a Class C Laboratory Unit exceeds 1,000 sf, a second means of access to an exit is required to be provided from the unit. Further, if there is a hazard located adjacent to the primary means of exit access that could obstruct the egress path in the event of an accident (e.g. an explosion hazard), a second means of access to an exit is required regardless of classification and size of the laboratory unit.

What are the limitations on exit access door configurations for my Laboratory Unit?

NFPA 45 contains requirements for door swing and the use of horizontal sliding doors that are dependent on the Laboratory Unit classification and are to be applied in conjunction with local building and life safety code requirements for doors. For example, exit access doors serving a Class A Laboratory Unit are required to swing in the direction of exit travel, whereas those serving a Class C Laboratory Unit are permitted to swing against the direction of exit travel if not otherwise required by building or life safety codes to swing in the direction of egress. Further, exit access doors serving Class C laboratory units are permitted to be horizontal sliding doors provided they comply with other local building and life safety code requirements.

If you have any questions or would like assistance with fire and life safety code compliance relative to laboratories, please do not hesitate to contact us.

Both building and fire codes require a building to be “fully sprinklered” for multiple reasons. Certain occupancy types, such as residential (Group R) or hazardous materials (Group H) occupancies are always required to be fully sprinklered. Many other occupancy types are required to be fully sprinklered when over a certain area, located a certain distance above/below grade, and/or based on occupant load. In Massachusetts, there are specific instances where the Massachusetts General Laws require full sprinkler protection. Fully sprinklering a building can also give certain benefits in design and construction such as increased height and area, longer egress travel distances, reduction in ratings for fire barriers, and elimination of certain fire alarm components. For all these conditions, the International Building Code (903.3.1.1) requires that sprinklers be installed throughout in accordance with the proper NFPA sprinkler standard – be it NFPA 13, 13R, or 13D – but there are exceptions. When can you call a building “fully sprinklered” when sprinklers really are not installed everywhere?

The first set of locations are those from the building code (IBC 903.3.1.1.1):

  1. Rooms where application of water causes a serious life or fire hazard
  2. Rooms where sprinklers are not desirable because of contents, where approved by the fire code official (such as rooms for storage of water-reactive materials)
  3. Generator and transformer rooms separated with 2-hour rated construction
  4. Rooms that are noncombustible with wholly noncombustible contents
  5. Fire service access elevator machine rooms and machinery spaces
  6. Machine rooms and spaces, control rooms and spaces associated with occupant evacuation elevators
  7. Certain bathrooms less than 55 square feet in R-1, R-2, and R-3 occupancies

The next set of locations are provided by NFPA 13, Standard for the Installation of Sprinkler Systems. For this discussion, we are using the 2013 edition as it is the edition currently adopted and in use in Massachusetts. Newer editions have slightly different criteria (and different locations within the standard itself). These locations are only for NFPA 13 sprinkler systems, and do not include the locations where sprinklers can be omitted which are identified in NFPA 13R, Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies or NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes. Both NFPA 13R and NFPA 13D have additional locations – such as attics and bathrooms less than 55 square feet – where sprinklers are not required.

  1. Noncombustible concealed spaces with minimal combustible loading
  2. Concealed spaces of noncombustible and limited combustible construction with limited access and not permitting occupancy or storage of combustibles
  3. Certain spaces above ceilings within combustible construction
  4. Concealed spaces filled with noncombustible insulation
  5. Concealed spaces over rooms less than 55 square feet
  6. Concealed spaces where the exposed materials are constructed entirely of fire retardant-treated wood
  7. Noncombustible concealed spaces where the heat content of the facing and substate of the insulation does not exceed 1,000 Btu per square foot
  8. Combustible soffits, eaves, overhangs, and decorative frame elements not over 4 feet in width, that are draftstopped into volumes less than 160 cubic feet, separated from the building with no openings or unprotected penetrations into the building, and with no storage beneath
  9. Noncombustible or limited-combustible, nonaccessible vertical duct, mechanical, or electrical shafts
  10. Noncombustible exit corridors where the exterior walls are at least 50 percent open
  11. Closets in dwelling units and hotels that are less than 24 square feet and the ceilings are noncombustible or limited combustible, or 6 square feet in hospital patient rooms.
  12. Two-hour rated electrical rooms for dry type electrical equipment only with no combustible storage
  13. Inside or underneath portable furniture
  14. Inside electrical equipment, mechanical equipment or air handling units not intended for occupancy

Additionally, in Massachusetts, there are several specific locations where sprinklers are not required:

  1. Certain spaces in telecommunications buildings that are provided with smoke detection and separated from the remainder of the building with 1-hour fire barriers and 2-hour floors.
  2. Noncombustible and limited combustible concealed spaces and plenums containing electrical, data, communications, and other cables as permitted by 527 CMR [plenum-rated cable].
  3. Transformer vaults meeting certain requirements
  4. Machine rooms of traction/drum hydraulic elevators, elevator hoistways, and elevator pits; sprinklers are also expressly prohibited from these spaces by 524 CMR Massachusetts Board of Elevator Regulations

It should be noted that Massachusetts specific exemptions or prohibitions on sprinkler installation in certain rooms may not be applicable in buildings subject to federal regulations; such as healthcare facilities regulated by Centers for Medicare & Medicaid Services (CMS) requirements, federal buildings where PBS-P100 Facilities Standards for Public Buildings Service, or Department of Defense Unified Facilities Criteria requirements are utilized. In those cases, the most restrictive requirements would apply and conflicts between the codes should be reviewed on a case-by-case basis.

Given the above criteria, there are many locations where sprinklers do not have to be installed for a building to be considered “fully sprinklered.” These locations depend on a number of factors with the design and intended use of the building and its spaces and can be a subject to the discretion of both the Registered Design Professional and Authority Having Jurisdiction involved. If you have questions as to whether sprinklers are required in a particular location, please contact our office at 617-500-7633 or info@crcfire.com to speak with our team.

In an era of increasingly complex building designs with advanced MEP/FP and life-safety systems, building signage is a simple, effective tool that can have a tangible benefit to first responders and fire department personnel.

In an emergency situation, responding personnel need to be able to quickly understand the building layout and the fire and life safety systems in order to effectively plan and conduct their emergency operations.

Building Codes and Referenced Standards provide a good baseline for minimum required signage.  For example, the International Building Code (911.1.6) requires the Fire Command Center to post clear information regarding the building size, floors, construction type, stair and egress information, fire protection systems, fuel sources, hazmat areas, and more.

NFPA Standards (including NFPA 1: Fire Code, NFPA 13: Standard for the Installation of Sprinkler Systems, and NFPA 14: Standard for the Installation of Standpipe and Hose Systems) have specific requirements for signage and labeling, with the goal of assisting the Fire Department with location, activation, and isolation of systems.   Common signs include those for sprinkler and standpipe control valves, drains, fire pump equipment, fire hose valves, and fire department connections (also see our blog post Fire Department Connection Signage – Code Red Consultants).

While Codes and Standards provide the minimum baseline, local jurisdictions may have additional requests they have found to be effective.  The design and construction team can work in collaboration with the local Authorities Having Jurisdiction to develop a signage strategy that will not only satisfy the Codes but also benefit the building occupants and responding emergency personnel.  Examples of some “best practice” signage can include:

  • Simple and Intuitive naming of stairwells and building levels (East/West, A/B, etc.)
  • Consistency with sign size, font, color, and material.
  • Additional wayfinding aides in obstructed or congested areas such as basements, mechanical equipment areas, and roofs. This can include robust signage, painted floors, additional lighting and exit signs, etc.
  • A consistent naming scheme amongst the MEP/FP trades and Architect, so system labels correspond with room names and numbers, stairs, floor level, etc.
  • Correct orientation of graphical signage (e.g. directional maps) based on the viewing position of the sign.

As building designs and systems get more and more complicated, it can be easy to overlook important details such as signage.  It’s good to remember that sometimes the simplest tools can be the most reliable and impactful, and a thoughtful signage strategy can go a long way in aiding emergency responders.

For more information on building signage please contact us at info@crcfire.com

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