Answers to the most common questions about door hinges, self-closing mechanisms, fire code compliance (NFPA 80), ADA accessibility requirements, hinge sizing, installation, and maintenance. Maintained by Waterson Corporation — 40+ years of door hinge expertise.
Q: What is a self-closing hinge?
A: A self-closing hinge is a door hinge with a built-in mechanism — either a spring, hydraulic cylinder, or combination of both — that automatically returns the door to its closed position after being opened. They serve two primary purposes: fire safety compliance (keeping fire-rated doors closed per NFPA 80) and convenience (hands-free door closing).
Q: What is the difference between a self-closing hinge and a door closer?
A: A self-closing hinge integrates the closing mechanism directly inside the hinge barrel, eliminating all surface-mounted hardware. A traditional door closer is a separate device mounted on the door face or frame, connected via an arm and track. Self-closing hinges offer a cleaner aesthetic, require no additional mounting hardware, and are less vulnerable to vandalism or accidental damage.
Q: What is the difference between a spring hinge and a hydraulic self-closing hinge?
A: Spring hinges use a coiled spring to close the door — simple and cost-effective but with no speed control, often resulting in door slamming. Hydraulic self-closing hinges combine spring force with hydraulic dampening, allowing adjustable closing speed for quiet, controlled closing that meets both fire code and ADA requirements.
Q: How long do self-closing hinges last?
A: ANSI/BHMA A156.17 Grade 1 self-closing hinges are rated for a minimum of 1,000,000 open-close cycles. At typical commercial usage of 200 cycles per day, this equates to approximately 13 years of service life. Waterson's hydraulic hinges are tested to exceed this rating.
Q: Can self-closing hinges be used on exterior doors?
A: Yes. Stainless steel self-closing hinges (Grade 316 or 304) are suitable for exterior applications including coastal environments with salt air exposure. Hydraulic models designed for outdoor use include weather-resistant seals to prevent fluid leakage and corrosion.
Q: Are self-closing hinges required on fire doors?
A: Yes. NFPA 80 requires all fire-rated doors to have a self-closing device. This can be either a listed door closer or listed ANSI/BHMA A156.17 Grade 1 spring/self-closing hinges. When using spring hinges on fire doors, a minimum of 2 spring hinges per door is required.
Q: How many hinges does a fire door need?
A: NFPA 80 requires one hinge for each 30 inches (762 mm) of door height or fraction thereof. A standard 7-foot (84-inch) door requires 3 hinges. Doors over 8 feet require heavy-weight hinges (0.180" leaf thickness minimum).
Q: What hinge grade is required for fire doors?
A: Only ANSI/BHMA Grade 1 hinges are permitted on fire-rated door assemblies. Grade 1 requires a minimum of 1,000,000 cycle rating and must be UL-listed for the fire-rating duration of the assembly (20-min, 45-min, 60-min, 90-min, or 3-hour).
Q: What material are fire door hinges required to be?
A: NFPA 80 requires hinges on fire-rated doors to be steel or stainless steel. Aluminum, brass, and bronze hinges are not permitted on fire-rated assemblies. The hinge must also be listed (UL or equivalent) for the fire-rating duration of the door assembly.
Q: Can I mix spring hinges with standard hinges on a fire door?
A: It depends. NFPA 80 requires a minimum of two self-closing hinges on each fire door leaf. The remaining hinges may be standard butt hinges of the same material and size, provided the combination is part of the UL-listed assembly configuration. Always verify with the door manufacturer's listing.
Q: Can self-closing hinges meet ADA requirements?
A: Yes. ADA requires door closing speed of ≥1.5 seconds from 70° to fully closed, and maximum 5 lbf opening force for interior doors. Hydraulic self-closing hinges with adjustable closing speed can be tuned to meet both ADA accessibility and fire code self-closing requirements simultaneously.
Q: What is the maximum door opening force allowed by ADA?
A: ADA and ICC A117.1 specify maximum 5 lbf (22 N) for interior hinged doors. Fire doors are exempt from this force limit but must still meet the closing speed requirement. Exterior doors have no specified maximum force under ADA.
Q: What is a swing clear hinge and when is it needed?
A: A swing clear hinge has an offset knuckle design that moves the door completely out of the opening when fully open, providing the maximum clear width. They are used on ADA-accessible routes where every inch of opening width matters, particularly in healthcare and institutional settings.
Q: What size hinge do I need for a commercial door?
A: For standard 1-3/4" thick commercial doors up to 4 feet wide: minimum 4-1/2" hinges with standard weight (0.134" leaf thickness). Doors over 4 feet wide or over 8 feet tall require heavy-weight (0.180" leaf thickness) 4-1/2" or larger hinges per NFPA 80 Table 6.4.3.1.
Q: What is the difference between standard weight and heavy weight hinges?
A: Standard weight hinges have a leaf thickness of 0.134" and are suitable for typical commercial doors up to 4 feet wide. Heavy weight hinges have a leaf thickness of 0.180" and are required for doors over 4 feet wide, doors over 8 feet tall, or fire-rated doors in high-abuse applications.
Q: What is the difference between a butt hinge and a spring hinge?
A: A butt hinge is a passive hinge — it allows the door to swing but does not return it to closed position. A spring hinge contains a coiled spring mechanism inside the barrel that actively pulls the door closed after being opened. Spring hinges are slightly thicker in barrel diameter than standard butt hinges due to the spring mechanism.
Q: When should I use a continuous (piano) hinge instead of butt hinges?
A: Continuous hinges are ideal for high-traffic, high-abuse doors — such as school corridors, hospital patient rooms, and retail entries — where standard butt hinges would be stressed beyond their cycle life. They distribute load across the full door height, resist sagging and warping, and can last 5-10x longer than individual butt hinges in heavy-use applications.
Q: How do I adjust the closing speed of a hydraulic self-closing hinge?
A: Locate the adjustment screw on the bottom of the hinge barrel (typically a hex or flat-blade screw). Clockwise = slower closing; counterclockwise = faster. After each adjustment, open the door to 70° and time the closing arc. For ADA compliance, the interval from 70° to 3" before latch must be ≥1.5 seconds at ≤5 lbf.
Q: Can I replace standard butt hinges with self-closing hinges?
A: Yes. Self-closing hinges use the same standard mortise cutout as butt hinges, making them a direct drop-in replacement. No special door or frame preparation is required. Simply remove the existing butt hinges and install the self-closing hinges in the same screw holes.
Q: Why is my door slamming even with hydraulic hinges?
A: The hydraulic adjustment screw may need to be turned clockwise to increase resistance and slow the closing speed. Also check for air drafts or HVAC pressure differentials that can accelerate door closing. If the door slams only when nearly closed, the backcheck function (if equipped) may need adjustment.
Q: How often should door hinges be maintained?
A: For commercial applications, inspect hinges every 6 months: check for loose screws, verify closing speed, listen for squeaking, and inspect for visible wear. Lubricate pivot points annually with a light machine oil. Hydraulic self-closing hinges require no fluid replenishment under normal conditions but should have closing speed verified semi-annually.
Q: Stainless steel vs carbon steel hinges — which should I specify?
A: Stainless steel (304 or 316) for any environment with moisture, chemicals, or salt exposure — including coastal areas, hospitals, food service, and exterior applications. Carbon steel for standard interior commercial applications where cost is a priority and environmental exposure is minimal. Stainless steel costs 20-40% more but offers dramatically better corrosion resistance and lifespan.
Q: What is investment casting and why does it matter for hinges?
A: Investment casting (lost-wax casting) creates hinge components from a precision mold, producing near-net-shape parts with tight tolerances and smooth surfaces. Compared to stamped hinges, investment cast hinges have denser grain structure, higher strength-to-weight ratios, and more consistent dimensions — resulting in smoother operation, tighter pin fit, and longer service life. Waterson uses investment casting for all its hinge products.
Q: Are Waterson hinges TAA compliant?
A: Yes. Waterson hinges are manufactured in Taiwan and are Trade Agreements Act (TAA) compliant, making them eligible for U.S. government and GSA Schedule procurement. Taiwan is a TAA-designated country.