Steel Doors vs. Wood Doors

Wood Door

Which type of doors perform better when comparing steel doors versus wood? Steel doors offer many advantages over traditional wood doors, making them a preferred choice for specifiers. Unlike wood doors, which are susceptible to warping, cracking, and rotting over time, hollow metal doors maintain their structural integrity even in the harshest conditions.

The quantitative and qualitative data below is based on extensive research including the use of independent testing agencies, standards organizations, and online information, plus interviews with door and frame industry professionals.

Performance characteristics were evaluated using quantitative tests such as measurements by a testing organization and/or defined industry standards. Qualitative evaluation of performance characteristics was primarily through examination of material attributes and interviews with door and frame experts.

Here are our findings.

Performance Tables

Fire Rating
Blast Resistance
Sound Transmission/Acoustics
Forced Entry Resistance
Tornado Resistance
Thermal Performance
Relative Performance – Sanitation (Anti-microbial Properties)
Relative Performance – Corrosion and Water Resistance
Relative Performance – Maintenance and Repair

Fire Rating

Steel, being a non-combustible material, does not contribute to the spread of fire. Steel is also the only door material that offers a 3-hour fire rating.

Wood is inherently flammable and cannot readily achieve a high fire rating – 90 minutes tends to be the high end. As the fire rating increases, the cost generally does too.

Relevant Test Methods/Standards:

• NFPA 80 – Standard for Fire Doors and Other Opening Protectives
• UL 10C – Standard for Positive Pressure Fire Tests of Door Assemblies

CONCLUSION

Steel doors have the best fire rating capabilities and are the sole door material to deliver a 3-hour fire rating. They are also generally priced lower than other fire rated doors.

Blast Resistance

Blast resistant steel door assemblies pass the common standards for blast resistant openings.

Wood doors are not cannot be manufactured to be blast resistant. They are not specified for blast resistant openings since they are unable to pass common industry test standards.

Relevant Test Methods/Standards:

• ASTM F2247 – Standard Test Method for Metal Doors Used in Blast Resistant Applications
• ASTM F2927 – Standard Test Method for Door Systems Subject to Airblast Loadings
• ASTM F1642 – Standard Test Method for Glazing and Glazing Systems Subject to Airblast Loadings

CONCLUSION

Steel doors pass blast resistant standards, whereas wood doors are not capable of being blast resistant.

Sound Transmission/Acoustics

Steel offers the highest STC rating of any door material. Single steel acoustic door ratings generally range from STC 32-55 (and up to 66 with highly specialized doors), with pairs generally rated up to STC 48. Steel acoustic doors can achieve a 3-hour fire rating. Embossments and vision lights are available also.

Wood doors have lower STC ratings and higher lifecycle costs. Wood acoustic door ratings generally range from STC 32-52, with pairs generally only rated to STC 44.

Relevant Test Methods/Standards:

• ASTM E90 – Standard Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Building Partitions and Elements
• ASTM E413 – Classification for Rating Sound Insulation
• ASTM E336 – Standard Test Method for Measurement of Airborne Sound Attenuation between Rooms in Buildings

CONCLUSION

Steel doors have the best STC performance characteristics. They are well suited to sound reduction specifications and offer lower lifecycle costs in those environments.

Forced Entry Resistance

Steel door assemblies pass the three commonly specified test criteria for forced entry resistance in government and non-government buildings.

Wood doors are not suited for forced entry resistance because the material is soft and susceptible to cracking and breaking.

Relevant Test Methods/Standards:

• ASTM F1233 – Standard Test Method for Security Glazing Materials and Systems,
• ASTM F3038 – Standard Test Method for Timed Evaluation of Forced-Entry-Resistant Systems
• SD-STD-01.01 – Forced Entry and Ballistic Resistance of Structural Systems

CONCLUSION

Due to its inherent strength and lower lifecycle costs, steel is the optimal and most commonly specified door material for forced entry resistant openings.

Tornado Resistance

Steel doors pass the tornado resistance tests of the two primary standards developers which includes testing wind speeds up to 250 mph.

No wood door, with or without metal sheathing, has successfully passed FEMA 361 so they are not listed for tornado resistance.

Relevant Test Methods/Standards:

• FEMA 361 – Safe Rooms for Tornadoes and Hurricanes
• ICC 500 – Standard for the Design and Construction of Storm Shelters

CONCLUSION

Steel is the only door material that is viable for tornado resistant opening applications.

Thermal Performance

Steel doors with polyurethane, polystyrene or honeycomb cores transmit little heat compared to other materials. Hollow metal doors with a steel stiffened core transfer the most heat of the steel core materials.

Wood doors transfer more heat than some steel doors, however their thermal transmittance is relatively low.

Relevant Test Methods/Standards:

• ASTM C1199 – Standard Test Method for Measuring the Steady-State Thermal Transmittance of Fenestration Systems Using Hot Box Methods
• ASTM C1363 – Standard Test Method for Thermal Performance of Building Materials and Envelope Assemblies by Means of a Hot Box Apparatus
• ASTM E1423 – Standard Practice for Determining Steady State Thermal Transmittance of Fenestration Systems

CONCLUSION

Steel’s thermal performance is directly related to its core. Wood doors transfer more heat than steel doors with polyurethane and steel stiffened cores.

Relative Performance – Sanitation (Anti-microbial Properties)

Stainless steel doors with a custom seamless edge have superior anti-microbial properties. They wash easily and sanitize thoroughly, making them a good choice for sanitary environments, such as food handling and medical.

Steel is well suited to environments requiring high levels of sanitation. It washes easily when specified with the appropriate finish and a custom seamless edge. Antimicrobial resin is available for additional protection.

Wood is naturally porous and difficult to sanitize. Antimicrobial resins are sometimes applied to wood specialty doors to improve the sanitation performance.

CONCLUSION

Other than all glass doors, stainless steel and steel doors have the best sanitation properties.

Relative Performance – Corrosion & Water Resistance

Stainless steel doors are commonly specified for environments requiring corrosion or water resistance. Type 316 is required for high salt or high chemical environments, such as coastal applications (salt) and indoor swimming pools.

Steel earned a medium performance rating for corrosion and water resistance. While naturally susceptible to rust, steel is a versatile material, and cost-effective galvanized coatings and applied finishes are readily available.

Wood does not corrode; however, water can degrade wood and cause mold. Because corrosive materials frequently are encountered in a moist environment, wood doors are not well suited to many corrosive environments.

CONCLUSION

Stainless steel doors offer the best performance for corrosion resistance versus wood.

Relative Performance – Maintenance & Repair

Steel doors provide superior performance because steel does not crack or dent easily. They can often be repaired in the field with body filler or re-welding for a relatively low cost which provides an economic advantage over wood doors.

Wood has the lowest relative performance in terms of maintenance and repair. Wood is susceptible to cracking and can be expensive to repair. Damaged wood doors are frequently replaced rather than repaired.

CONCLUSION

Steel doors provide the best price/performance advantage for maintenance and repair.