A protection device worn on a human body and protects a head of the human body includes a base portion attachable to the human body, and a protection unit having a honeycomb structure or a bellows structure, held by the base portion, and being reversibly switchable between a folded orientation in which the protection unit is folded and an unfolded orientation in which the protection unit is unfolded from the folded orientation and thus the protection unit covers the head of the human body, the protection unit being provided with a fixed end fixed to the base portion and a free end not fixed to the base portion, the protection unit is folded in a state where the free end is close to the fixed end, and the protection unit is unfolded around the head while the free end separates from the fixed end.

A collapsible helmet is formed as an arcuate layered structure openable into a honeycomb protective configuration. The arcuate layered structure is formed from a number of arcuate segments each covering only part of the helmet. Each segment is oriented so that an extensional cell direction of the honeycomb structure is radial for a middle-region. The arcuate layered structure is preferably bounded by arcuate end plates which engage with each other when the helmet is open to form a rigid loop encircling a bottom edge of the helmet.

A head protection device includes an airbag receiving case flexibly bent along a user's neck to allow both ends to be releasably fastened, an airbag folded and stored in the airbag receiving case, and an inflator part which includes a battery and supplies inflated gas to the airbag. The airbag includes an occipital part which protects a back part of the user's head, a front/upper head part which protects a front part and an upper part of the head, a right part which protects a right area of the head, and a left part which e protects a left area of the head.

Hood assemblies with disposable hoods are provided. In one implementation, a single-use, disposable hood includes a hood material sized to extend over a user's head and down to a neck/shoulder region. The hood material includes a face shield opening extending through the hood material. The hood further includes a fixed face shield attached to the hood material and covering the face shield opening; two or more hood connecting members positioned along an outer periphery of the face shield opening; and a removable stick-on face shield guard sized to extend over the face shield opening and be removably attachable to the hood, the removable stick-on face shield guard comprises a transparent face shield material, and two or more face shield guard connecting components being attachable to and/or connectable to and/or engageable with said hood material or said fixed face shield.

Single-use, disposable helmets, hoods, and helmet/hood assemblies are disclosed. Methods of making and using single-use, disposable helmets, hoods, and helmet/hood assemblies are also disclosed.