NFPA, IBC, and ISO Construction Classifications, in Comparison

Building construction classifications are determined based on the buildings structural elements and the fire-resistance rating of those elements.  These elements include, structural framing, exterior and interior bearing walls, and floor and roof construction and their supporting features.

There are three governing “bodies” that provide building construction classifications.  Each group provides a different classification designation, however, they all contain the same construction elements and fire-resistance ratings of materials. These three organizations are:

• National Fire Protection Association (NFPA)
• International Building Code (IBC)
• Insurance Services Office (ISO)

The National Fire Protection Association defines each construction type and classification in NFPA 220, Standard on Types of Building Construction. The International Building Code defines these construction types and classifications in Chapter 6, Types of Construction. The Insurance Services Office defines these construction types and classification in its Construction Briefs page on its website.

The chart below shows a side-by-side comparison of all three construction type classifications.

Click here for a printer-friendly version of this chart.

Type I and II - Fire Resistive, Noncombustible

NFPA: “...those types in which the fire walls, structural elements, walls, arches, floors, and roofs are of approved noncombustible or limited combustible materials.”

IBC: “...those types of construction in which the building elements...are of noncombustible materials.”

ISO Class 6 (Fire Resistive): “The exterior bearing walls and load-bearing portions of exterior walls must be of noncombustible materials or of masonry, but exterior nonbearing walls and wall panels may be slow burning, combustible, or with no fire-resistance rating.”

ISO Class 5 (Modified Fire Resistive): “...Building construction consists of fire resistive materials such as masonry and protected steel materials not less than 4” thick.”

ISO Class 4 (Masonry Noncombustible): “...Buildings with walls made of masonry, consisting of concrete block, reinforced masonry and can be combined with steel framing..”

ISO Class 3 (Noncombustible): “...Buildings with exterior walls, floors and roofs of noncombustible or slow-burning materials.”

Type III - Ordinary

NFPA: “... that type in which exterior walls and structural elements that are portions of exterior walls are of approved noncombustible or limited-combustible materials...fire walls, interior structural elements, walls, arches, floors, and roofs are entirely or partially of wood…”

IBC: “...that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of any material permitted by this code.”

ISO Class 2 (Joisted Masonry): “...Buildings with exterior walls of masonry or fire-resistive construction rated for not less than one hour and with combustible floors and roofs.”

Type IV - Heavy Timber

NFPA: “...that type in which fire walls, exterior walls, and interior bearing walls and structural elements that are portions of such walls are of approved noncombustible or limited combustible materials...other interior structural elements...shall be of solid or laminated wood without concealed spaces…with the allowable dimensions of [this code]...”

IBC: “...that type of construction in which the exterior walls are of noncombustible materials and the interior building elements are of solid or laminated wood without concealed spaces.”

Type V - Wood Frame

NFPA: “...that type in which structural elements, walls, arches, floors, and roofs are entirely or partially of wood…”

IBC: “...that type of construction in which the structural elements, exterior walls and interior walls are of any materials permitted by this code.”

ISO Class 1 (Frame): “...Buildings with exterior walls, floors and roofs of combustible material.”

The FPO Effectiveness Tool

Listen to an audio presentation of this post.

In my latest book, Fire Prevention Blueprint, I outline seven disciplines that are required for building an effective fire prevention organization. But, how can you rate your current level of effectiveness? To answer this question we have developed the “FPO balance wheel”.

The “FPO balance wheel” addresses each of the seven disciplines required for an effective fire prevention organization. This tool will help to assess where your organization is, and what areas need to be improved on to achieve maximum effectiveness.

How to use the wheel:

• Use the questions below as a guide to accurately rate yourself on each discipline. 
• See the center of the circle as 1 and the outer edge as 10. (1 is the worst, 10 is the best)
• Rate your organization on its effectiveness in that specific discipline, by placing a dot in the numeric range. Also, write the rank number beside the dot.
• After you have ranked each section with a dot, connect all the dots with a straight line. This new ‘shape’ is a visual representation of current balance in your organization.

Example of Completed FPO Balance Wheel

PRINT YOUR OWN FPO BALANCE WHEEL AND THIS GUIDE

Know Your Community

• Have you completed a CRA (community risk assessment)?
• Do you know the seven content areas that need to be assessed for the CRA?
• Do you know the specific risks and hazards within each area of your community?
• Do you know where to get data from and how to use it?

Have a Plan

• Do you have a specific and separate ‘operations manual’ for your fire prevention organization?
• Does this manual fully outline all the tasks and responsibilities of your organization?
• Do you have a strategic plan in place that effectively addresses the communities fire protection and life safety needs?
• Does your fire prevention plan accurately outline the programs and strategies that will be utilized to reduce, mitigate, or eliminate risks posed to the community?
• Is your plan or strategy made up of realistic and achievable goals?
• Have you created a long-range plan for the success of your organization?

Enforce the Code

• Are you currently conducting inspections in all buildings at regular intervals?
• Have you classified the occupancy risk of each structure?
• Do you know how many inspections are required annually, biennially, and triennially?
• Have you pre-planned your structures so you know the risks and hazards they pose?
• Have you established inspection frequency for all buildings?
• Do your personnel have the ‘soft skills’ necessary for gaining compliance?

Conduct Plan Review and Field Inspections

• Do you know the nine elements of effective plan review?
• Do your personnel have a clear understanding of the functions and benefits of plan review?
• Is your organization involved in the commissioning and integrated systems testing process?

Investigate Fire Incidents

• Do you have personnel in place to conduct fire investigations?
• Are company officers properly trained to conduct preliminary fire investigations?
• Are you maximizing the data gathered from these investigations?
• Are you familiar with NFPA 921 and the six-step investigation methodology?
• Are your personnel equipped with all the necessary tools to conduct a thorough investigation?

Educate the Public

• Are your public education programs interactive and engaging?
• Are your public education programs relevant to community needs?
• Have you built strategic partnerships with community stakeholders?
• Do your public educators know how to communicate effectively?

Be Adequately Staffed

• Are you tracking the time requirements for fire prevention tasks?
• Do you know the minimum number of personnel needed to accomplish fire prevention tasks?
• Do you know the five step system for determining minimum staffing needs?
• Are your employees appropriately challenged?
• Do you know why people want to work for you and how to keep them?

Review your balance wheel rankings for each section. After looking at your whole wheel consider the following questions for improvement.

1. List four things that this wheel exercise tells you about your FPO.
2. Did you rate the majority of sections as a 5 or less, or 6 or higher?
3. How many sections are 5 or less?
4. What areas do you want to most change or improve?
5. What actions do you need to take to balance out your wheel or make needed changes?
6. What resources will you need to make this happen?

PRINT YOUR OWN FPO BALANCE WHEEL AND THIS GUIDE

Fire Sprinkler Design Guide [for AHJ's]

This interactive guide, and book, will enable the fire plan reviewer or inspector to quickly answer the most important questions for approval and acceptance of a fire sprinkler system.

• Does the structure require a fire sprinkler system?
• Is the occupancy and commodity properly classified?
• Are plastics properly identified and protected?
• Does the rack storage need in-rack sprinklers?
• Will there be any obstructions to the discharge pattern?
• How are the cloud ceilings protected?

Clicking on the title for each section will take you to a full article on the topic. Before you get started, I recommend you download and print my glossary of "Key Terms  for NFPA 13 Storage". This convenient tool eliminates the need to search multiple pages for clarifications by listing the most used terms and definitions on a single page. 

Sprinklers where required…

Reading through the NFPA standards, one consistently comes upon the phrase "sprinklers where required".  However, in order to find where they are, or may be, required, involves some searching through the code book.  

The below is a tool that can be used as a quick guide to what occupancies require fire sprinklers, and where the code can be referenced.

Download the sprinkler requirements guide.

Guide to NFPA 13 Occupancy and Commodity Classifications

Perhaps you are conducting a fire inspection or survey and you notice that the hazard or commodity classification on the hydraulic calculation plate at the riser seems odd for the actual contents of the structure.  Or, you are sitting down to do a plan review, the occupancy hazard and commodity class is listed. Are these classifications correct based on the use of the structure?

NFPA 13, Standard for the Installation of Sprinkler Systems, chapter five defines occupancy hazard and commodities classifications for the design and installation of sprinkler systems. In book form, this information can sometimes be difficult to recall. This slideshow presentation can be utilized as a reference to quickly review and confirm occupancy and commodity classifications.

Download the slideshare cheat sheet.

What kind of plastic is it?

To provide effective fire sprinkler protection within a structure, the hazard classification and commodity must be known. For the protection of rack storage, the storage and shelving configuration must be known. Due to the high speed and temperature of burning plastics, they require special consideration.  NFPA 13, Standard for the Installation of Sprinkler Systems, requires all plastics, elastomers, and rubber, to be classified as Group A, Group B, or Group C.

Fire Protection Requirements for Rack Storage

What are the requirements for rack storage? Are in-rack sprinklers required? How can rack storage sprinkler requirements be determined?

Fire protection requirements for rack storage are addressed in NFPA 13, Standard for the Installation of Sprinkler Systems.  

• Chapter 13, Protection of Miscellaneous and Low-Piled Storage
• Chapter 14, Protection for Palletized, Solid-Piled, Bin Box, Shelf, or Back-to-Back Shelf Storage of Class I through Class IV Commodities
• Chapter 15, Protection for Palletized, Solid-Piled, Bin Box, Shelf, or Back-to-Back Shelf Storage of Plastic and Rubber Commodities
• Chapter 16, Protection of Rack Storage of Class I through Class IV Commodities
• Chapter 17, Protection of Rack Storage of Plastic and Rubber Commodities

To determine which chapter to go to for fire protection requirements, there are three questions that must be answered:

1. What is stored?
2. How is it stored?
3. How high is it stored?

Sprinkler Obstructions and Discharge Patterns

Important to fire sprinkler effectiveness is sprinkler discharge pattern development. A fire sprinkler system should be designed in a manner that provides full water coverage from the fire sprinkler system. Inherent building construction or design elements can pose potential obstructions to the full coverage or discharge pattern of the sprinkler system.  However, these buildings and elements must still be protected. NFPA 13, Standard for the Installation of Sprinkler Systems, provides sprinkler coverage guidance for these obstructed areas.

To determine the proper application it must first be determined if the construction is obstructed or unobstructed.  Then it must be determined if the obstruction is continuous or noncontinuous.

Protecting the Cloud

Cloud ceiling: a suspended ceiling that covers only a portion of a room or space below

These cloud ceilings present unique challenges to fire sprinkler installation. The solution to these challenges are not always easily found clearly in the pages of NFPA 13. However, by applying the obstruction and clearance principles the solution will make itself clear.

What is the "small room" rule?
In conducting plan reviews or fire sprinkler field inspections you may have heard, or seen, the invocation of the “small room" rule. Though not specifically stated in NFPA 13 as the “small room" rule, it is a combination of several code sections within the standard that can be utilized to provide advantages in hydraulic calculations and flexibility in sprinkler spacing.

BONUS: Doorway to Hell - An Analysis of Potential Fire Sprinkler Performance

In 1984 tragedy struck the Great Adventure theme park when 8 teenagers were killed in the Haunted Castle attraction.  The fire, believed (not proven) to have been started by a an individual playing with a lighter, has seen a great deal of controversy, and differing of opinions, through out the years. The resulting code changes created the special amusement requirements in NFPA 101.  

In this video, Jack Fairchild, a certified fire protection specialist with Ballinger A/E, discusses the history and impact of this fire, and guides us through his analysis of the potential effectiveness of fire sprinkler systems, he answers the question, "Would sprinklers have saved these kids?"

What kind of plastic is it?

To provide effective fire sprinkler protection within a structure, the hazard classification and commodity must be known. For the protection of rack storage, the storage and shelving configuration must be known. Due to the high speed and temperature of burning plastics, they require special consideration.  NFPA 13, Standard for the Installation of Sprinkler Systems, requires all plastics, elastomers, and rubber, to be classified as Group A, Group B, or Group C.

A complete list of Group A plastics is provided in 5.6.4.1 and Table A.5.6.4.1, of NFPA 13. This group of plastics includes rubber, poly(s)-, cellulosics, and nylon. Group A plastics are further divided into expanded or unexpanded. Expanded plastics are “low-density materials” commonly referred to as “foam plastics”. Unexpanded plastics must meet one, of six, criteria listed in listed in section 5.6.4..1.1.2. Group B plastics include chloro-, fluoro-, and silicone products. There are seven materials classified as Group C plastics.  This group include the polyvinyl- products. A complete list is provided in section 5.6.4.3.

Sprinkler design criteria for the protection of plastics is outlined in Chapter 15 and Chapter 17 of NFPA 13. If the plastics are Group A and do not exceed 5 feet in height then the protection requirements of Chapter 13, Protection of Miscellaneous and Low-Piled Storage, can apply. For all plastic or rubber commodities that exceed 5 feet in height, section 15.2.2 outlines the fire protection requirements. For clarity and protection requirements the decision tree provided in figure 15.2.2.1 of this standard should be referenced.

If the stored items are plastic or rubber commodities and on rack storage the protection requirements of Chapter 17 shall be enforced. This section has a decision tree that must be followed based on the group of plastics being protected, as well as alternate provisions for systems that do not meet minimum design requirements. If plastic or rubber commodities on rack storage is encountered, this chapter should be closely examined.