Decoding Waterson Hinges: What SA, SA1, SB Really Mean

“Why do you guys have so many terms like this? What is SA, SA1, DS… I don’t get it!”

If you’ve ever stood at a project site holding a hinge stamped SA or SB, wondering whether it controls swing, latch speed, or hold-open, you know clarity matters. The wrong decoding Waterson hinges can compromise NFPA 80 compliance, ADA usability, or fire-rating performance. That’s why Waterson uses a code system: to identify the exact mechanism built into each hinge.

Decoding Waterson Hinges : What Each Mechanism Does

SA – Spring + Swing Control

• S (Spring Power): Provides the self-closing force.
• A (Swing Power): Controls door speed from 90° to 20°.
• Use Case: Doors that must reliably close without slamming, but don’t require fine latching control. Common in commercial interiors.

SA1 – Spring + Latching Control

• S (Spring Power): Provides closing force.
• A1 (Latching Speed): Controls the last 20° of closing—critical for latch engagement.
• Use Case: Fire-rated and security doors where final positive latching is required by code.

SB – Spring + Hold-Open

• S (Spring Power): Provides closing force.
• B (Hold-Open): Holds the door open at 85° ±5°.
• Use Case: Healthcare, hospitality, or facilities where a door must stay open temporarily for equipment, carts, or occupant flow, without additional hardware.

HA – Hydraulic + Swing Control

• H (Hydraulic Damping): Controls swing or latch speed, or any range in between.
• A (Swing Speed): Specifically manages 90° to 20° of closing.
• Use Case: High-traffic or noise-sensitive environments (schools, offices, residential towers) where soft-close and quiet operation are essential.

HS – Hydraulic + Spring Hybrid

• H (Hydraulic Damping): Smooths closing motion.
• S (Spring Power): Delivers reliable closing force.
• Use Case: Heavy-duty installations needing both power and controlled damping—for example, exterior or high-cycle commercial entries.

NM – No Mechanism

• N (None), M (None): Functions as a standard hinge, no self-closing or damping.
• Use Case: Non-rated openings where mechanical assistance is unnecessary.

Take-away Quick Guide

• SA: Self-closing + swing control
• SA1: Self-closing + latch control
• SB: Self-closing + hold-open
• HA: Hydraulic soft-close swing
• HS: Hydraulic + spring hybrid
• NM: Standard hinge, no mechanism

Why the Codes Matter

Waterson doesn’t just ship “one hinge fits all.” Each hinge set is engineered with different functions and purposes, and the code tells you exactly what it does:

• SA → Closing force + swing control
• SB → Closing force + hold-open at 85°
• SA1 → Closing force + final latching control

The next time you see SA, SB, or HA stamped on a Waterson hinge, you’re not looking at random letters—you’re reading a mechanical blueprint. That blueprint determines how your door will perform under code, under stress, and over millions of cycles.

How to Identify the Code on Each Waterson Hinge

If you look closely at the hinge plates in the image, you’ll see engraved codes—for example:

• SA (left hinge)
• SB (middle hinge)
• SA1 (right hinge)

These codes are always stamped directly onto the hinge leaf. They’re not stickers, not packaging marks, but permanent engravings. That’s intentional: so installers, inspectors, and maintenance teams can immediately know what mechanism combination is inside the hinge without having to second-guess.

Self Closing Spring Loaded Hinges vs Traditional Overhead Door Closer

Waterson Stainless Steel Self Closing Spring Loaded Hinges

Waterson stainless steel self closing hinges combines the function of an overhead closer and a hinge into a single, sleek component—complete with optional hold-open and door-stop features. Designed for commercial openings, gates, and glass doors, these hinges are easy to install and adjust to meet ADA and ICC A117.1 standards for opening force, while ensuring quiet and secure closure. Crafted from durable stainless steel, they are NFPA 80 compliant, UL 3-hour fire-rated, and built to perform reliably in both interior and all-weather exterior environments. See all our features.

In addition to these performance advantages, Waterson offers flexible customization services. As a direct custom hinge manufacturer, we can tailor hinge sizes, finishes, and especially hinge leaf designs to meet the specific structural needs of your doors. This makes our hinges an ideal solution for door manufacturers seeking custom options that integrate seamlessly with their existing frames.

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Please note that Waterson Closer Hinges start from a size of 4″x4″. If you’re in need of smaller self-closing hinges, we’d recommend checking out some other resources! Also, we only provide single acting closer hinges. Thank you.

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