(a) Applicability.--The benefits provided for by this subchapter shall apply to all individuals employed in any capacity or holding positions in or, in the case of a volunteer firefighter, rendering services recognized and accepted by a city creating a fund and board in accordance with provisions of this subchapter. This subchapter shall not apply to employees of departments, bureaus or offices which are otherwise protected by pensions authorized by this chapter.

(b) Membership.--Any volunteer firefighter may become a member of a fund as of the date of the volunteer firefighter's original employment or of the inception of the fund, whichever is later, upon the volunteer firefighter making back contributions and if the volunteer fire company or its board of trustees employing and paying the volunteer firefighter agrees to contribute and contributes to the fund the required sums.