| Basic Connections, Perimeter, and Lateral Splay Bracing |
Requirements |
| Minimum intersection strength limits @ MT / CT |
180 lbs |
| Vertical hanger wire 12-gauge @ 4' o.c. |
Required |
| Connection device from vertical wire to the structure above must sustain min 100 lbs |
Required |
| Main tee classifications |
Heavy-duty |
| 1 in 6 max plumb of vertical hanger wires |
Required |
| Perimeter vertical hanger wires not more than 8" from wall |
Required |
| Grid end/wall clearance |
Min 3/4" |
| Perimeter closure (molding) width |
Min 2 " |
| Grid connection to perimeter attached on two adjacent walls |
Required |
| Perimeter tee ends tied together |
Required |
| Horizontal restraint (splay wires or rigid bracing) within 2" of intersection and splayed 90° apart at 45° angles |
Required |
| Compression posts (struts) 12' o.c. in both directions, starting 6' from walls |
Required |
| Splay bracing connection strength 200 lbs or the design load, whichever is greater |
Required |
| Partition attachment |
Bracing independent of ceiling splay bracing |
| Seismic separation joint4 |
Required for areas > 2,500 sq. ft. (or full height partition) |
| Rigid bracing for ceiling plane elevation changes |
Required |
| Light Fixture Attachment |
Requirements |
| Light fixture (all types) mechanically attached to grid NEC 410-16 (two per fixture unless independently supported) |
Required |
| Surface-mounted fixtures attached to grid |
Not required |
| Pendant-hung fixtures directly supported from structure with 9-gauge wire (or approved alternative) |
Required |
| Rigid lay-in or can light fixtures |
|
| < 10 lbs – one wire to structure (may be slack) |
Required |
| 10 to 56 lbs – two wires from housing to structure (may be slack) |
Required |
| > 56 lbs – supported directly to structure by approved |
Required |
| Service Applications |
Requirements |
| Air terminals |
|
| < 20 lbs – positively attached to grid |
Required |
| 20 to 56 lbs – positively attached to grid and two wires to structure (may be slack) |
Required |
| > 56 lbs – directly supported to structure |
Required |
| Sprinkler heads and other penetration clearance |
Min 2" dia. opening or a swing joint |
| Cable trays and electrical conduit independently supported and braced |
Required |
Notes
1. Refers to CISCA installation recommendations for zones 3-4 via ASCE 7.
2. The above information is correct to the best of our knowledge at the date of issuance. Because codes continue to evolve, check with a local official prior to designing and installing a ceiling system. This is only intended as a quick reference.
3. Required for ceilings larger than 1,000 square feet.
4. Where substantiating design calculations are not provided.
