Short answer. The word surface names a mounting family; for the models shown on NGP's G37 page, the publisher says to mount the automatic door bottom on the push side. source Use that instruction to identify the correct design and questions to ask—not to relocate hardware on a rated or egress door.
Check the correct catalog page and family
NGP's G37 surface section has multiple seal/material variants: for example, 220NA is listed with black neoprene, while 220SA is listed with black silicone. source The same page warns that models 220, 221, 229 and 310 require handing information and says units under 36 inches in its described handed subset are not field-reversible. source These limits cannot be blindly transferred to a different model or publication revision.
The heavy-duty family on printed G39 includes 420NA, 520NA and 680A with visibly different seal details, again under a push-side-mounted heavy-duty heading. source Importantly, that page also pictures surface-mounted and half-mortise-mounted conditions separately. source A drawing of one configuration is not proof of clearance or compatibility with the other.
Push-side identification: observation workflow
| Look at | What you can safely record | Next decision |
|---|---|---|
| Door when normally operated | The face toward which it swings when pushed open | Establish the term push side without removing anything |
| Actual bottom housing | Photograph lengthwise housing position and seal, not only a small cross-section | Compare with the same NGP model drawing |
| Label and documents | Whole hardware model, finish, revision and door rating information, if legible | Distinguish specification from an unidentified field installation |
| Threshold and gap | Photograph contact surface and whether an obstruction exists | Ask a qualified specifier to determine clearance, not to guess a cut |
Decision tree: If model + document revision + installed arrangement match, retain the record for the responsible hardware professional. If only the phrase “surface automatic bottom” matches, find the exact part. If the door is rated, has an egress function, lacks an interpretable label, or fails to close or latch normally, stop non-authorised work and seek qualified review.
Do not treat NGP's product icons as independent approval for a particular altered fire door. This article intentionally omits drilling positions, field-cut instructions, latching adjustment and any substitute product recommendation. It answers which orientation the printed issuer evidence describes—not whether a modification is permitted.
Official sources and precise sections
- NGP Gasketing & Automatic Door Bottoms / printed code NGP-CAT-GAS-0424-A; issue date not inferred,
PDF index 37 / printed G37; Surface heading and first bullet— https://ngp.com/ngp/cache/file/EE31761B-3DDD-4760-A388E860CF060E3F.pdf - NGP Gasketing & Automatic Door Bottoms / printed code NGP-CAT-GAS-0424-A; issue date not inferred,
PDF index 37 / printed G37; 220NA/220SA rows— https://ngp.com/ngp/cache/file/EE31761B-3DDD-4760-A388E860CF060E3F.pdf - NGP Gasketing & Automatic Door Bottoms / printed code NGP-CAT-GAS-0424-A; issue date not inferred,
PDF index 37 / printed G37; bullet End Caps and note 2— https://ngp.com/ngp/cache/file/EE31761B-3DDD-4760-A388E860CF060E3F.pdf - NGP Gasketing & Automatic Door Bottoms / printed code NGP-CAT-GAS-0424-A; issue date not inferred,
PDF index 39 / printed G39; heavy-duty illustrations and rows— https://ngp.com/ngp/cache/file/EE31761B-3DDD-4760-A388E860CF060E3F.pdf - NGP Gasketing & Automatic Door Bottoms / printed code NGP-CAT-GAS-0424-A; issue date not inferred,
PDF index 39 / printed G39; Surface Mounted / Half Mortise Mounted drawing labels— https://ngp.com/ngp/cache/file/EE31761B-3DDD-4760-A388E860CF060E3F.pdf