Type C Gypsum Board or MGO: Making the Right Choice for Fire Safety

Type C gypsum board stands out as one of the best fire-resistant materials you can buy. Your choice of material could mean the difference between life and safety. Type C gypsum board gives you fire protection for at least two hours, which is by a lot more than the one-hour protection that type X drywall offers. MGO boards are a great match for these materials too. They can handle extreme temperatures up to 1,800°F and come with natural fire resistance and environmental benefits.

Fire safety is crucial in building and renovation projects, so you need to know your options for fire-rated gypsum boards. The difference between Type C and Type X is clear - Type C has special additives and better formulations with extra glass fiber that help it stay strong during fires. Type C's fire ratings are impressive, but MGO board takes it further - it doesn't burn at all and fights off mold and water damage too. Your choice between these materials really depends on what you need, what you can spend, and how you plan to use it.

Let's get into both options and help you figure out if Type C drywall's fire rating benefits or MGO board's advantages work better for your project.

Material Composition and Fire Behavior

The way fire-resistant building materials are made determines how they behave in fires. Learning about these differences helps you choose between type C gypsum board and MGO board for vital applications.

Type C Gypsum Board: Glass Fiber and Additives

Type C gypsum board lifts fire resistance through a special formula that builds on standard gypsum technology. The core has calcium sulfate dihydrate (gypsum) with more glass fibers than Type X boards. These fibers help keep the structure intact during fires by creating a reinforcing mesh throughout the core.

Type C gypsum board stands out because of its special additives. The board contains vermiculite, a mineral that expands in high temperatures. This expansion helps fight against gypsum's natural shrinking during calcination and keeps the panel intact by preventing cracks that let fire through. On top of that, it can achieve fire ratings of two hours or more in UL assemblies.

MGO Board: Natural Magnesium Oxide Core

MGO boards get their amazing fire resistance from magnesium oxide, a natural mineral. These boards mix magnesium oxide with magnesium sulfate that act as binding agents. Most makers prefer magnesium sulfate formulas because they don't have the corrosion risks that come with chloride ions.

The core becomes stronger with different types of fibers (glass, wood, or synthetic) and light fillers like perlite and vermiculite. This mix creates a dense, mineral-based material that stays stable when it gets wet, unlike wood-based panels.

How Each Material Reacts to Fire Exposure

Type C gypsum board and MGO board react very differently to fire. Gypsum boards work through calcination. The water molecules in the gypsum core (about 21% by weight) turn to steam between 150°C and 190°C. This change absorbs heat energy and creates a temporary barrier against heat transfer.

MGO boards work differently. They resist fire through their material's natural properties instead of changing phases. The material stays stable even above 750°C, and the boards can handle temperatures up to 800°C (1,472°F) without burning. Tests showed that MGO panels didn't spread flames even at 1,200°C (2,192°F).

There's another reason these materials are different. Gypsum boards eventually break down as water evaporates, but MGO boards keep their shape and strength in high temperatures. Both products are safe and don't release toxic fumes in fires, especially when you have MGO boards.

Fire Resistance Ratings and Certifications

Fire resistance ratings are vital measures that help builders and architects select the right materials to keep people safe. These standardized tests give a scientific way to compare different building products in controlled fire conditions.

Type C Drywall Fire Rating: 2+ Hours in UL Assemblies

Type C gypsum board stands out with its fire resistance performance. Tests show it can withstand fire for two hours or more. The boards get their superior protection from special additives and extra glass fiber reinforcement. These components help them stay structurally sound during long fire exposure.

Underwriters Laboratories (UL) gives these panels specific names like FSW-C and eXP-C. These designations show their high-level fire-resistance qualities. Manufacturers created Type C boards to cut down the layers needed in fire-rated assemblies. To cite an instance, floor-ceiling assemblies that needed two layers of 5/8" Type X can get the same ratings with a single Type C layer when used with resilient channels.

The difference between Type C and Type X products is significant. Type C products meet all ASTM requirements for Type X, but Type X products don't always qualify as Type C. This matters a lot in choosing materials for specialized fire-rated assemblies.

MGO Board Fire Rating: Class A, Zero Flame Spread

MGO boards show remarkable fire ratings in standard tests. These panels earn Class A fire ratings with zero flame spread. Fire cannot travel on MGO board surfaces - a unique feature among wall materials.

The ASTM E84 test (Steiner Tunnel Test) shows that quality magnesium oxide boards have zero flame spread and smoke development. European standards give MGO boards their highest non-combustible rating - Class A1.

MGO boards keep their structure at temperatures up to 1,200°C (2,192°F). They don't burn or release toxic fumes. Some MGO systems can resist fire for up to four hours in the right assemblies because of this exceptional performance.

ASTM and UL Standards for Fire Rated Gypsum Board

Type C gypsum board and MGO boards must pass strict testing protocols from trusted authorities. ASTM E119, the main standard, looks at complete assemblies instead of single materials to determine hourly fire ratings. These assemblies get specific designations based on their controlled burn test results.

UL adds extra testing through its certification process. Fire-rated gypsum boards need thorough assessment to get UL Classification for fire resistance, surface-burning characteristics, and non-combustibility. UL-classified products must stay compliant through regular third-party inspections.

Quality assurance in the industry relies on standard testing methods. These methods make sure all manufacturers deliver consistent performance. The Gypsum Association's Fire Resistance Design Manual lists approved fire-rated assembly designs for Type X and Type C products. Products that meet these standards will protect buildings reliably when installed correctly.

Durability, Moisture, and Mold Resistance

Wall materials need more than just fire protection to last. Their durability depends on how well they handle moisture and physical impact. The materials' makeup plays a crucial role in tough environments.

Water Resistance: MGO vs Type C in Wet Areas

These materials handle moisture quite differently. MGO boards take in just 0.34% water, while gypsum boards absorb nearly 3% under the same conditions. This huge gap affects how they work in humid spaces.

High-quality magnesium oxide boards stay strong even after 100 days underwater. They don't warp or swell, which makes them perfect for bathrooms, kitchens, and outdoor use.

Type C gypsum boards tell a different story. Even with water-repellent additives, they break down in long-term moisture exposure. You can find special moisture-resistant versions, but they still fall short of MGO's performance in wet areas. These boards handle quick moisture exposure fine but struggle in damp spots.

Mold Resistance Testing: ASTM D3273 and D6329

ASTM D3273 and D6329 give us clear ways to measure mold resistance. The D3273 test puts materials through a four-week lab test that speeds up mold growth. A perfect score of 10 means no mold showed up during testing.

MGO boards ace these tests with perfect scores because their inorganic makeup gives mold nothing to feed on. The board's dense, mineral-based structure naturally keeps mold, mildew, and bacteria away.

Type C gypsum with mold-resistant features beats standard drywall, but its paper surface contains organic materials that can feed fungi when wet for too long. Most manufacturers admit that no material is completely "mold-proof".

Impact Strength and Structural Integrity Over Time

MGO boards beat gypsum products in mechanical strength. Quality magnesium boards show impact strength ratings of 4.5 kilojoules or more, which beats standard drywall's 1 kilojoule rating. This makes them ideal for busy places like schools and hospitals.

The numbers tell the story: MGO panels reach 18-27 MPa in flexural strength, while gypsum only hits 5.6 MPa. MGO boards keep all their flexural strength after getting wet, but gypsum panels lose 36-52% of their strength after similar wet-dry cycles.

MGO's fiberglass mesh creates an internal framework that spreads force evenly. This leads to better resistance against cracks, dents, and loose fasteners. Such toughness means lower maintenance costs and fewer replacements over a building's life.

Application Suitability and Use Cases

Your construction project's specific requirements will determine the right fire-resistant material. Each option comes with its own set of advantages that work best in different situations.

Best Use for Type C: Schools, Hospitals, Ceilings

Type C gypsum board works great for interior applications where fire safety rules are strict. You'll find it's a perfect fit for interior walls and ceilings in homes and commercial buildings. The board really stands out when used horizontally - think roof-ceiling setups, floor-ceiling assemblies, and horizontal shaftwall systems.

Schools and hospitals benefit most from type C gypsum board since these buildings need extra evacuation time. Architects often choose this material for crucial areas like stairwells, elevator shafts, and mechanical rooms. Wood frame construction gets a big advantage too - you can achieve a 1-hour fire rating with just one layer of Type C and resilient channels, instead of needing two layers of 5/8" Type X.

Best Use for MGO: Kitchens, Bathrooms, Exterior Walls

MGO boards really shine where you need protection against moisture and want something tough:

·       Wet areas: These boards work great in bathrooms, kitchens, and saunas thanks to their moisture resistance

·       Exterior applications: They're perfect for sheathing, cladding systems, and exterior walls

·       High-impact zones: Schools, hospitals, and busy areas that need extra durability love these boards

MGO boards stand out because they work well both inside and outside. You can even use them for exterior roofing without worrying about water damage. Their ability to handle extreme temperatures makes them ideal for industrial buildings or areas prone to natural disasters.

Type C vs MGO in Fire-Rated Assemblies

Both materials bring something special to fire-rated assemblies. We developed Type C gypsum board to cut down the number of layers needed in multilayered fire-resistant builds. This means thinner walls in 2-hour rated assemblies.

MGO panels give you a simpler way to fireproof exterior walls. You can save on materials and labor costs by using just one layer of MGO on the outside while keeping the fire resistance you need. On top of that, it stays solid when exposed to extreme heat, which stops flames and hot gasses from getting into wall cavities.

Cost, Availability, and Environmental Impact

Material selection depends on both practical factors and technical specs. The final choice between type C gypsum board and MGO alternatives comes down to budget constraints, environmental impact, and how easy the products are to source.

Price Comparison: Type C vs MGO Board

These materials have a significant price difference. A 5/8-inch-thick, 4×8-foot sheet of Type C gypsum board costs about USD 12.00. MGO boards are much pricier at USD 1.50 to USD 3.50 per square foot. This makes MGO boards cost 2-4 times more upfront.

MGO's economics make more sense in the long run. The material lasts much longer and needs fewer replacements, especially in damp areas. Some insurance providers even lower their premiums when buildings use materials with higher fire ratings.

Sustainability: Recycled Content and Emissions

Each material brings its own green benefits. Type C gypsum board's facing paper comes from 100% recycled materials. MGO boards produce 22% less CO2 than standard cement boards.

Some manufacturers have earned GREENGUARD Gold Certification for their fire-resistant products. This certification shows they emit low VOCs. MGO boards stand out because they don't contain harmful substances like formaldehyde or asbestos.

Availability by Region and Brand Options

Type C gypsum board is accessible to more people across North America through major manufacturers. The market's 30-year history means steady supply at competitive prices. MGO boards are gaining popularity but might be harder to find in some regions.

Comparison Table

Conclusion

The choice between Type C gypsum board and MGO board for fire safety comes down to several important factors. Both materials give you excellent fire resistance, though they work differently. Type C gypsum board uses glass fibers and vermiculite in its makeup to achieve impressive two-hour-plus fire ratings. This makes it a great fit for commercial buildings. MGO board takes things up a notch with its resistance to extreme temperatures up to 1,800°F and zero flame spread ratings.

These materials differ a lot in their durability too. MGO boards handle moisture much better, soaking up just 0.34% water compared to gypsum's 3%. This makes them perfect for bathrooms and kitchens. They're also much tougher, with an impact strength of 4.5+ kilojoules versus gypsum's 1 kilojoule - a big plus in high-traffic areas.

Money plays a big role in the decision. The original cost of Type C gypsum board is easier on the wallet at about $12 per standard sheet. MGO costs more at $1.50-$3.50 per square foot. In spite of that, you should weigh this price difference against MGO's longer life and lower maintenance needs, especially in tough environments.

Your project's specific needs will determine the best choice. Type C gypsum board works great for interior spaces like schools, hospitals, and ceiling assemblies where budgets are tight but fire safety is crucial. MGO boards shine in places that need both toughness and fire resistance. Kitchens, bathrooms, exterior walls, and industrial facilities all benefit from MGO's complete protection.

Both options meet strict safety standards and will keep you protected from fire if installed right. Your choice between Type C gypsum and MGO should balance your current budget against long-term performance needs, environmental conditions, and your building project's fire rating requirements.

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