ASTM E84 Explained: Flame Spread, Class A Ratings & Construction Requirements

When evaluating building materials, temporary construction walls, or fire safety documentation, understanding ASTM E84 is essential. Yet many professionals confuse ASTM E84 ratings with fire resistance ratings, creating unnecessary confusion during specification reviews, compliance discussions, and project planning.

While terms such as ASTM E84, Class A fire rating, flame spread index, smoke developed index, and one-hour fire rating are often used together, they measure very different aspects of fire performance. Understanding those differences is critical for architects, contractors, facility managers, and code officials responsible for making informed decisions about material selection and project safety.

This guide explains:

• What ASTM E84 measures

• How flame spread and smoke development ratings work

• What Class A, B, and C classifications mean

• How ASTM E84 differs from ASTM E119

• Why material ratings and assembly ratings are not the same thing

• What project teams should know when evaluating temporary construction walls and building materials

What Is ASTM E84?

ASTM E84 is one of the most widely recognized fire testing standards used in North American construction. Developed by ASTM International, the test evaluates the surface burning characteristics of materials when exposed to fire.

More specifically, ASTM E84 measures how quickly flames spread across the surface of a material and how much smoke is generated during testing.

Because of this, ASTM E84 is frequently referenced in building specifications, product documentation, construction submittals, and code compliance discussions. It provides a standardized way to compare materials and better understand how they may contribute to flame spread and smoke generation during a fire event.

You may also hear ASTM E84 referred to as the Steiner Tunnel Test, named after the testing apparatus used to evaluate materials under controlled conditions.

What ASTM E84 Measures

ASTM E84 evaluates two key performance indicators:

• Flame Spread Index (FSI)

• Smoke Developed Index (SDI)

Together, these measurements form the basis for Class A, Class B, and Class C fire classifications.

ASTM E84 ratings are frequently referenced in building codes, project specifications, product submittals, and authority having jurisdiction (AHJ) reviews. Understanding what the standard measures—and what it does not—can help project teams avoid costly misunderstandings during design, procurement, and compliance reviews.

What ASTM E84 Does Not Measure

One of the most common misconceptions is that ASTM E84 determines whether a wall, barrier, or assembly is fire-rated.

It does not.

ASTM E84 does not evaluate:

• Fire resistance

• Structural integrity during a fire

• How long a wall assembly can withstand fire exposure

• One-hour or two-hour fire ratings

• Complete wall assembly performance

Those requirements are typically evaluated using different standards, such as ASTM E119, which measures the fire endurance of complete assemblies.

Understanding this distinction is critical because a material can achieve a favorable ASTM E84 classification while still not qualifying as a fire-rated wall assembly.

What Is a Class A Fire Rating?

A Class A fire rating is the highest ASTM E84 classification commonly used to describe the surface burning characteristics of a material. Because many building codes and project specifications reference Class A materials, understanding what this designation means—and what it does not mean—is critical when evaluating fire safety requirements.

Materials that achieve a Class A rating demonstrate low flame spread characteristics during ASTM E84 testing and are often specified in hospitals, airports, commercial buildings, educational facilities, and other occupied environments where fire and life safety are important considerations.

However, one of the most common misconceptions in construction is assuming that a Class A material is automatically a fire-rated assembly.

A Class A rating simply describes how a material performs during an ASTM E84 test.

Class A vs. Class B vs. Class C

ASTM E84 classifications are determined by a material's Flame Spread Index (FSI), which places materials into one of three categories:

Materials with lower Flame Spread Index values demonstrate slower flame propagation during testing and generally receive higher classifications.

What Flame Spread Index Is Required for Class A?

To achieve a Class A rating, a material must receive a Flame Spread Index between 0 and 25.

This means flames spread relatively slowly across the material's surface compared with materials that receive Class B or Class C classifications.

For this reason, Class A materials are often specified in projects where reducing flame spread is a design consideration.

Does Class A Mean Fire-Rated?

Not necessarily.

While Class A materials demonstrate favorable flame spread characteristics, ASTM E84 does not evaluate how long a material or wall assembly can withstand fire exposure. As a result, a Class A material may be part of a fire-rated assembly—but a Class A rating alone does not make a product or wall system fire-rated.

In simple terms:

• ASTM E84 evaluates flame spread and smoke development.

• ASTM E119 evaluates fire resistance and endurance.

The two standards measure different performance characteristics and should not be used interchangeably.

Common Misconceptions About Class A Ratings

Before selecting materials for a project, it is important to understand what a Class A rating does—and does not—mean.

A Class A rating does not automatically mean:

• The material is one-hour fire-rated

• The finished wall assembly is fire-rated

• The product meets all project code requirements

• The material has been tested as part of a complete assembly

Instead, Class A should be viewed as one important piece of a larger fire and life safety evaluation process.

To understand how materials achieve Class A, Class B, or Class C classifications, it helps to look more closely at how ASTM E84 testing is conducted and how flame spread and smoke development are measured.

How ASTM E84 Determines Class A, B, and C Ratings

Understanding ASTM E84 classifications starts with understanding how the test is performed.

Often referred to as the Steiner Tunnel Test, ASTM E84 evaluates how a material behaves when exposed to a controlled fire environment. During testing, a sample material is installed in a tunnel-like apparatus and exposed to a flame at one end. As the test progresses, evaluators measure two primary factors:

• How quickly flames spread across the material's surface

• How much smoke is generated during the test

These measurements are then compared against established reference materials to determine a Flame Spread Index (FSI) and Smoke Developed Index (SDI).

The Flame Spread Index is used to assign materials to Class A, Class B, or Class C classifications based on established ASTM E84 thresholds.

In general, lower Flame Spread Index values indicate slower flame propagation across a material's surface. Because slower flame spread can help limit fire growth, materials with lower FSI values receive higher classifications.

How ASTM E84 Ratings Are Calculated

ASTM E84 is a comparative test rather than a pass-or-fail test.

Instead of determining whether a material is simply "safe" or "unsafe," the standard compares a material's performance against benchmark materials tested under the same conditions.

This allows architects, contractors, manufacturers, and code officials to evaluate how different materials behave during testing using a consistent methodology. These ASTM classifications help project teams compare materials using a standardized testing methodology and common performance benchmarks.

As a result, ASTM E84 ratings are commonly referenced in:

• Building codes

• Product specifications

• Construction submittals

• Material evaluations

• Authority Having Jurisdiction (AHJ) reviews

Why Comparative Testing Matters

Not all building materials contribute to fire growth in the same way.

Some materials allow flames to spread rapidly across their surfaces, while others help slow the progression of fire. Similarly, some materials generate significantly more smoke than others when exposed to fire.

ASTM E84 provides a standardized framework for comparing these characteristics, helping project teams make more informed decisions when selecting materials for occupied buildings and temporary construction environments.

However, it is important to remember that ASTM E84 evaluates material performance—not the fire resistance of a complete wall assembly.

That distinction becomes especially important when evaluating temporary construction walls, fire-rated barriers, and other systems where overall assembly performance may be required.

Understanding Flame Spread Index (FSI)

One of the most important measurements produced by ASTM E84 testing is the Flame Spread Index (FSI).

The Flame Spread Index measures how quickly flames travel across the surface of a material during testing. Rather than measuring how hot a fire becomes or how long a material survives exposure to fire, FSI focuses specifically on the rate at which flames spread.

In general, lower Flame Spread Index values indicate slower flame propagation, while higher values indicate faster flame spread.

This distinction is important because rapidly spreading flames can contribute to faster fire growth and increase the likelihood that a fire will spread beyond its point of origin.

Why Flame Spread Matters

When a fire occurs, the materials within a space can influence how quickly the fire develops and spreads.

Materials with lower flame spread characteristics can help slow the progression of fire along exposed surfaces, providing additional time for emergency response and occupant evacuation. Materials with higher flame spread characteristics may allow flames to move more rapidly through a space.

For this reason, many building codes and project specifications establish flame spread requirements for specific applications and occupancy types.

Understanding Flame Spread Index Values

Flame Spread Index values determine whether a material falls within the Class A, Class B, or Class C classification ranges established by ASTM E84.

In general, lower values indicate slower flame propagation across a material's surface, while higher values indicate faster flame spread.

For example, a material with a Flame Spread Index of 15 would fall within the Class A range, while a material with a Flame Spread Index of 100 would fall within the Class C range.

Because ASTM E84 is a comparative test, these values help project teams evaluate how materials perform relative to one another under standardized testing conditions.

What Flame Spread Index Does Not Tell You

Although Flame Spread Index is an important fire safety metric, it does not provide a complete picture of fire performance.

FSI does not indicate:

• How long a material can withstand fire exposure

• Whether a wall assembly is fire-rated

• Whether a product meets all project code requirements

• How a complete system performs when installed in the field

Those considerations may require additional testing, certifications, or assembly evaluations depending on project requirements.

Understanding these limitations helps prevent one of the most common mistakes in fire safety discussions: assuming a favorable Flame Spread Index automatically means a material or wall system is fire-rated.

Understanding Smoke Developed Index (SDI)

While flame spread often receives the most attention, smoke generation is another critical component of ASTM E84 testing.

The Smoke Developed Index (SDI) measures the amount of smoke produced by a material during the ASTM E84 test.

Like Flame Spread Index, SDI is a comparative measurement that helps evaluate how materials perform under standardized fire testing conditions.

Why Smoke Matters

In many fire incidents, smoke presents a significant life safety concern.

Dense smoke can:

• Reduce visibility

• Make evacuation more difficult

• Complicate emergency response efforts

• Increase risks for building occupants

Because of these concerns, building codes and project specifications frequently consider smoke development alongside flame spread when evaluating materials.

How Smoke Developed Index Is Used

ASTM E84 reports both Flame Spread Index and Smoke Developed Index results together because they provide complementary information about a material's behavior during fire exposure.

For example, two materials may have similar flame spread performance but generate different amounts of smoke during testing. Evaluating both measurements helps project teams gain a more complete understanding of fire performance characteristics.

Smoke Developed Index and ASTM Classifications

Although ASTM E84 classifications are primarily associated with Flame Spread Index ranges, Smoke Developed Index remains an important part of the evaluation process.

Many Class A materials not only demonstrate low flame spread characteristics but also maintain relatively low smoke development values.

For this reason, both measurements are often reviewed during product evaluations, submittal reviews, and code compliance discussions.

What Smoke Developed Index Does Not Measure

Like Flame Spread Index, Smoke Developed Index has limitations.

SDI does not measure:

• Toxicity of smoke

• Fire resistance of assemblies

• Structural performance during a fire

• Duration of fire protection

Instead, it serves as one piece of a broader fire safety evaluation framework.

Together, Flame Spread Index and Smoke Developed Index form the foundation of ASTM E84 classifications and help explain how Class A, B, and C ratings are assigned.

While Flame Spread Index and Smoke Developed Index help explain how materials behave during ASTM E84 testing, they do not answer an equally important question: how long can a wall assembly withstand fire exposure? To answer that question, it is important to understand another commonly referenced fire safety standard: ASTM E119.

ASTM E84 vs. ASTM E119: What's the Difference?

One of the most common sources of confusion in fire safety discussions is the difference between ASTM E84 and ASTM E119.

Because both standards are associated with fire performance, many people assume they measure the same thing. In reality, they evaluate very different characteristics and serve different purposes.

Understanding this distinction is critical when reviewing product specifications, evaluating temporary construction walls, or determining whether a material or assembly meets project requirements.

ASTM E84 vs. ASTM E119 Comparison

What ASTM E84 Measures

ASTM E84 evaluates how a material behaves when exposed to fire on its surface.

Specifically, the test measures:

• Flame Spread Index (FSI)

• Smoke Developed Index (SDI)

The results help determine whether a material receives a Class A, Class B, or Class C classification.

Because ASTM E84 focuses on surface burning characteristics, it is commonly used to evaluate building materials such as panels, finishes, insulation products, and other components used in construction.

What ASTM E119 Measures

ASTM E119 evaluates something entirely different.

Rather than focusing on a material's surface characteristics, ASTM E119 measures the ability of a complete assembly to resist fire over a specified period of time.

Examples include:

• Wall assemblies

• Floor assemblies

• Ceiling assemblies

• Structural building components

Results are typically expressed as time-based ratings such as:

• One-hour fire rating

• Two-hour fire rating

• Three-hour fire rating

These ratings indicate how long the tested assembly maintained its performance during controlled fire exposure conditions.

Why the Difference Matters

A material can achieve a favorable ASTM E84 classification and still not qualify as a fire-rated assembly. For example, it may receive a Class A rating because it demonstrates low flame spread characteristics. However, that same material has not necessarily been tested as part of a complete wall assembly under ASTM E119.

This distinction becomes particularly important when evaluating:

• Fire-rated temporary construction walls

• Occupied renovation projects

• Healthcare construction environments

• Airport and transportation projects

• Other code-sensitive applications

In these situations, project teams may need documentation demonstrating assembly performance—not just material performance.

Material Ratings vs. Assembly Ratings

It may be helpful to think about the difference this way:

ASTM E84 answers: How does this material behave when exposed to fire on its surface?

ASTM E119 answers: How long can this complete assembly withstand fire exposure?

Both standards play important roles in fire safety planning, but they are not interchangeable.

Understanding the difference can help contractors, facility teams, architects, and AHJs make more informed decisions when evaluating materials, assemblies, and temporary containment systems.

When Projects Require More Than ASTM E84

ASTM E84 provides valuable information about flame spread and smoke development, but some projects require additional documentation related to fire resistance and assembly performance. When one-hour ratings, fire-rated temporary barriers, or documented assembly testing are required, ASTM E84 may be only one part of the evaluation process.

In our guide to Fire-Rated Temporary Construction Walls: Requirements, Ratings & Compliance, we explore:

• One-hour fire ratings

• ASTM E119 testing

• Listed assembly certification

• AHJ considerations

• Fire-rated temporary containment systems

Why Material Ratings Are Not the Same as Assembly Ratings

By this point, it's clear that ASTM E84 and ASTM E119 evaluate different aspects of fire performance. However, another common misconception can create confusion during product evaluations and project planning:

Many people assume that if a material has a favorable fire rating, the finished wall or assembly automatically shares that same rating.

In reality, material ratings and assembly ratings are not the same thing.

Understanding Material Testing

Many building products are tested individually to evaluate specific performance characteristics.

For example, ASTM E84 testing evaluates:

• Flame spread

• Smoke development

• Surface burning characteristics

These results provide valuable information about how a material performs under controlled testing conditions.

However, building materials are rarely used in isolation.

When installed in the field, materials become part of larger systems that may include:

• Framing

• Fasteners

• Joints and seams

• Doors and access points

• Penetrations

• Other construction components

As a result, the performance of a finished assembly can differ from the performance of an individual material.

Understanding Assembly Testing

Assembly testing evaluates how multiple components perform together as a complete system.

Rather than testing a single material, assembly testing examines how the finished construction performs when installed according to a specific design or configuration.

Depending on project requirements, assembly testing may evaluate:

• Fire resistance

• Structural integrity

• Smoke control

• Overall system performance

This distinction is especially important when projects require documented fire resistance ratings or code compliance verification.

Why This Matters During Construction Projects

Construction teams often review product documentation, specifications, and submittals to determine whether materials and systems meet project requirements.

Without understanding the difference between material testing and assembly testing, it can be easy to assume that a product's material-level performance automatically applies to the finished installation.

In many cases, that assumption may not be appropriate. For example:

• A material may achieve a Class A rating under ASTM E84.

• The finished wall assembly may require separate testing to demonstrate fire resistance.

• Project-specific requirements may call for documentation beyond material-level testing.

Understanding these distinctions helps project teams ask better questions during design reviews, procurement decisions, and compliance discussions.

Why AHJs Often Focus on Assembly Performance

Authorities Having Jurisdiction (AHJs) are ultimately responsible for interpreting and enforcing applicable codes and requirements within their jurisdictions.

When reviewing construction projects, AHJs may focus on how a complete system performs rather than how an individual material performed during testing. This is particularly common in:

• Occupied renovation projects

• Healthcare construction

• Airports and transportation facilities

• Data centers

• Other code-sensitive environments

Because project requirements vary, it is important to verify what documentation may be required before construction begins.

A Practical Rule of Thumb

When evaluating fire performance documentation, it can be helpful to ask two questions:

1. How did the material perform during testing? This is where standards such as ASTM E84 help provide answers.

2. How does the complete assembly perform when installed? This is where assembly testing, fire resistance evaluations, and project-specific requirements often become important.

Understanding the difference between these two questions can help contractors, facility teams, architects, and code officials make more informed decisions and avoid costly misunderstandings later in the project.

As we'll discuss next, these considerations become especially important when evaluating temporary construction walls and barriers used in occupied renovation environments.

ASTM Fire Ratings for Temporary Construction Walls

Temporary construction walls play an important role in occupied renovation projects. They help separate construction activities from building occupants, maintain cleaner work environments, and support project phasing in facilities that must remain operational during construction.

In healthcare facilities, airports, data centers, commercial buildings, and other occupied environments, temporary barriers are often expected to do more than simply divide a space. Depending on the project, they may also be required to support specific fire and life safety objectives.

This is where understanding ASTM fire ratings becomes important.

Why Fire Performance Matters for Temporary Barriers

Construction projects can introduce unique fire safety considerations. Temporary conditions may include:

• Modified egress routes

• Temporary partitions and barriers

• Active construction operations

• Increased combustible materials

• Changes to building systems and occupancy patterns

Because of these factors, project teams often evaluate the fire performance characteristics of temporary construction barriers before installation.

The level of documentation required may vary based on:

• Building type

• Occupancy classification

• Scope of work

• Local code requirements

• Authority Having Jurisdiction (AHJ) expectations

Understanding ASTM E84 in Temporary Construction Applications

When evaluating temporary construction walls, ASTM E84 can help project teams understand how the materials used in a barrier perform with respect to:

• Flame spread

• Smoke development

• Surface burning characteristics

This information may be useful during:

• Product evaluations

• Specification reviews

• Submittal processes

• Compliance discussions

However, it's important to remember that ASTM E84 only evaluates material performance. It does not determine whether a temporary wall assembly is fire-rated or how long it can withstand fire exposure.

Why AHJs May Request Additional Documentation

Depending on the project, Authorities Having Jurisdiction (AHJs) may require information beyond ASTM E84 classifications.

This is particularly common in occupied, code-sensitive environments where fire and life safety considerations are elevated. Examples may include:

• Healthcare renovations

• Airport construction projects

• Data centers

• Manufacturing facilities

• Educational campuses

In these situations, AHJs may review not only the materials used within a temporary barrier, but also how the complete system performs when installed.

Because requirements vary by project and jurisdiction, it is important to engage stakeholders early and understand what documentation may be required before construction begins.

Temporary Walls in Occupied Renovation Environments

Occupied renovations present unique challenges because construction must occur alongside ongoing operations.

Project teams are often balancing multiple priorities, including:

• Occupant safety

• Business continuity

• Infection prevention

• Noise and disruption management

• Fire and life safety requirements

As a result, temporary wall systems are frequently evaluated on a combination of factors rather than a single performance metric.

Fire safety considerations may be one component of a broader project strategy that includes operational, environmental, and compliance objectives.

Choosing the Right Temporary Construction Barrier

The appropriate temporary barrier solution depends on the specific requirements of the project.

Important questions may include:

• What fire safety requirements apply to the project?

• Is material-level testing sufficient?

• Are assembly-level evaluations required?

• What documentation may be requested by the AHJ?

• How will the barrier impact occupants and operations?

Understanding the answers to these questions can help project teams make more informed decisions while reducing the risk of delays, compliance challenges, or costly rework.

For projects requiring fire-rated temporary barriers, assembly testing, or documented fire resistance performance, additional considerations may apply beyond ASTM E84 classifications alone.

In the next section, we'll answer some of the most common questions professionals ask about ASTM E84 fire ratings and fire safety requirements.

Common Questions About ASTM E84 Fire Ratings

What is ASTM E84?

ASTM E84 is a standardized fire test method used to evaluate the surface burning characteristics of building materials. Often referred to as the Steiner Tunnel Test, ASTM E84 measures how quickly flames spread across a material's surface and how much smoke is generated during testing.

The results are used to calculate a Flame Spread Index (FSI) and Smoke Developed Index (SDI), which help determine whether a material receives a Class A, Class B, or Class C classification.

What does ASTM E84 test?

ASTM E84 evaluates two primary performance characteristics:

• Flame Spread Index (FSI)

• Smoke Developed Index (SDI)

The test is designed to help architects, contractors, manufacturers, and code officials compare how different materials perform when exposed to fire under controlled testing conditions.

ASTM E84 does not evaluate fire resistance, structural integrity, or the performance of complete wall assemblies.

Is ASTM E84 required by code?

Building codes and project specifications frequently reference ASTM E84 classifications for certain materials and applications, but requirements vary depending on the jurisdiction, occupancy type, building use, and project specifications.

Because code requirements differ from one project to another, it is important to review applicable regulations and consult with project stakeholders and Authorities Having Jurisdiction (AHJs) when evaluating fire safety requirements.

What is a Class A fire rating?

A Class A fire rating is the highest ASTM E84 classification and is assigned to materials with a Flame Spread Index between 0 and 25.

Class A materials are often specified in hospitals, commercial buildings, educational facilities, airports, and other occupied environments where fire and life safety are important considerations.

It is important to remember that a Class A rating describes surface burning characteristics—not fire resistance.

What is a good ASTM E84 rating?

Lower Flame Spread Index values generally indicate slower flame spread during testing.

Materials that achieve a Flame Spread Index between 0 and 25 receive a Class A classification, the highest ASTM E84 classification commonly referenced in commercial construction.

However, the appropriate rating for a project depends on applicable codes, specifications, occupancy requirements, and project-specific conditions.

Does Class A mean fire-rated?

Not necessarily.

A Class A rating indicates that a material performed favorably during ASTM E84 testing, but it does not automatically mean the material or finished assembly is fire-rated.

Fire-rated assemblies are typically evaluated using different standards, such as ASTM E119, which measures fire resistance and endurance over a specified period of time.

A material may achieve a Class A rating without being part of a tested fire-rated assembly.

What is Flame Spread Index (FSI)?

Flame Spread Index (FSI) measures how quickly flames travel across the surface of a material during ASTM E84 testing.

The lower the Flame Spread Index, the more slowly flames spread across the tested surface.

FSI values are used to determine whether a material receives a Class A, Class B, or Class C classification.

What is Smoke Developed Index (SDI)?

Smoke Developed Index (SDI) measures the amount of smoke generated by a material during ASTM E84 testing.

Because smoke can significantly impact visibility, evacuation efforts, and emergency response, smoke development is an important part of evaluating a material's overall fire performance.

ASTM E84 reports both Flame Spread Index and Smoke Developed Index results to provide a more complete picture of material behavior during fire exposure.

Does ASTM E84 mean one-hour rated?

No. ASTM E84 does not evaluate how long a material or assembly can withstand fire exposure.

A one-hour fire rating is typically established through assembly testing standards such as ASTM E119, which evaluate the fire resistance of complete wall, floor, or ceiling assemblies.

ASTM E84 and ASTM E119 measure different performance characteristics and should not be used interchangeably.

What is the difference between ASTM E84 and ASTM E119?

ASTM E84 evaluates the surface burning characteristics of materials, including flame spread and smoke development.

ASTM E119 evaluates the fire resistance of walls, floors, ceilings, structural members, and other building elements when exposed to fire under controlled testing conditions.

In simple terms:

• ASTM E84 measures how materials behave when exposed to fire on their surface.

• ASTM E119 measures how long building elements can withstand fire exposure.

Both standards are important, but they answer different questions and serve different purposes.

Do temporary construction walls need ASTM fire ratings?

The answer depends on the project.

Some temporary construction barriers may require documentation related to flame spread, smoke development, fire resistance, or other performance criteria based on project conditions and applicable requirements.

Healthcare facilities, airports, data centers, occupied renovation projects, and other code-sensitive environments often involve additional fire and life safety considerations.

Project teams should review applicable requirements early and verify what documentation may be required before selecting a temporary construction barrier.

Takeaways

ASTM E84 is one of the most widely referenced fire safety standards in construction because it provides a consistent way to evaluate flame spread and smoke development characteristics of building materials. Understanding these ratings helps contractors, facility teams, architects, and code officials make more informed decisions about material selection and project safety.

However, ASTM E84 is only one piece of the fire safety puzzle. While it measures surface burning characteristics, it does not evaluate fire resistance or the performance of complete wall assemblies. For projects requiring documented fire-rated barriers, additional testing standards and assembly certifications may apply.

Understanding the difference between material ratings and assembly ratings can help project teams improve compliance, reduce confusion, and make better-informed decisions when evaluating temporary construction walls and other building materials.

If your project requires fire-rated temporary barriers, one-hour fire resistance, or documented assembly performance, understanding how ASTM E84 and ASTM E119 work together is an important next step.

Explore our guide to Fire-Rated Temporary Construction Walls: Requirements, Ratings & Compliance to learn more about fire-rated assemblies, testing standards, and compliance considerations for occupied renovation projects.