Side Curtain Airbag / Head Airbag

Side curtain airbags, also known as head airbags, are tubular airbags installed along both sides of the roof rails. They deploy during side-impact collisions or rollovers, covering the front and rear side window areas to provide head protection for outboard occupants, while effectively preventing them from being ejected from the cabin or injured by shattered glass.

Installation Location and Protective Functions

Side curtain airbags are typically positioned along the roofline above the front and rear seats, extending from the A-pillar to the C-pillar (or D-pillar). When an impact occurs, they deploy downwards from the roof like a curtain, covering the entire side window area to create a protective cushion between the occupants' heads and hard surfaces such as the windows and B-pillars.

Head Protection: In a side-impact collision, even if the point of impact is away from the occupant, inertia can cause the head to whip violently to the side. Side curtain airbags provide comprehensive head protection, significantly cushioning the impact force.
Ejection Prevention: In severe side collisions or rollover accidents, the deployed curtain covers the window aperture, preventing occupants from being thrown out of the vehicle due to door deformation.
Protection from Debris: The deployed curtain acts as an effective shield against flying glass shards during an impact, protecting occupants' faces and eyes from injury.

Operating Conditions

Side curtain airbags typically deploy in moderate to severe side impacts or rollovers, depending on the severity of the crash, angle of impact, and vehicle speed. In minor side scrapes or frontal/rear collisions, side curtain airbags generally will not deploy.

Difference from Other Side Airbags

Comparison Aspect	Side Airbag	Side Curtain Airbag (Head Airbag)
Installation Location	Outer bolster of seat backrest	Roof rails (A-pillar to C-pillar)
Protected Area	Torso (Chest/Abdomen/Pelvis)	Head
Coverage Area	Front row only (available for rear in select models)	Full continuous coverage across front and rear rows
Deployment Direction	Deploys forward (towards door panel)	Deploys downward (curtain-style)

Both systems usually work in tandem during a side impact, safeguarding different parts of the occupant's body.

Key Safety Precautions

To ensure side curtain airbags operate properly and deliver optimal protection, the following precautions must be observed:

Keep the Airbag Path Clear: Never hang clothes, air fresheners, ornaments, or any accessories on the roof grab handles or the area above the windows. Upon deployment, these items can be launched as dangerous projectiles, causing secondary injuries.
Do Not Modify the Headlining: Any aftermarket modification to the roof headlining or sun visor area can disrupt the airbag's deployment path and speed.
Proper Roof Rack Installation: If the vehicle is fitted with roof racks, ensure that the mounting hardware does not interfere with the airbag's deployment zone.

Daily Precautions

For vehicles equipped with side curtain airbags, it is recommended to avoid applying excessively thick window tinting films or decorative stickers on side windows to prevent extra debris risks during deployment. As with all supplementary restraint systems, if the SRS warning light on the instrument cluster remains illuminated or flashes, it indicates a potential system fault that should be inspected by a professional technician as soon as possible.