This section shall apply [1] to—

each employee of the Senate whose compensation is paid from the appropriation for Salaries, Officers and Employees under the following headings:

(A) Office of the Secretary, including individuals employed under authority of section 6538 of this title;

(B) Office of the Sergeant at Arms and Doorkeeper, except employees designated as “special employees”; and

(C) Offices of the Secretaries for the Majority and the Minority;

(2) each employee of the Senate authorized by Senate resolution to be appointed by the Secretary of the Senate or the Sergeant at Arms and Doorkeeper, except employees designated as “special employees”; and

(3) each employee of the Capitol Guide Service established under section 2166 [2] of this title.

For purposes of this section—

(1) Except as provided in paragraph (2), an employee to whom this section applies shall be paid, during any period of continuous creditable service, additional annual compensation (hereinafter referred to as “longevity compensation”) at the rate of $482 for (A) each year of creditable service performed for the first five years and (B) each two years of creditable service performed during the twenty-year period following the first five years.

(2) The amount of longevity compensation which may be paid to an employee, when added to his regular annual compensation, shall not exceed the maximum annual compensation which may be paid to Senate employees generally as prescribed by law or orders of the President pro tempore issued under authority of section 4571 of this title.

For purposes of this section—

(A) creditable service includes (i) service performed as an employee described in subsection (a), (ii) service performed as a member of the Capitol Police or as an employee of the United States Capitol Telephone Exchange while compensation therefor is disbursed by the Clerk of the House of Representatives, and (iii) service which is creditable for purposes of this section as in effect on September 30, 1978;

(B) in computing length of continuous creditable service, only creditable service performed subsequent to August 31, 1957, shall be taken into account, except that, in the case of service as an employee employed under authority of section 6538 of this title, only creditable service performed subsequent to January 2, 1971, shall be taken into account; and

(C) continuity of creditable service shall not be deemed to be broken by separations from service of not more than thirty days, by the performance of service as an employee (other than an employee subject to the provisions of this section) whose compensation is disbursed by the Secretary of the Senate or the Clerk of the House of Representatives, or by the performance of active military service in the armed forces of the United States, but periods of such separations and service shall not be creditable service.

(4) Longevity compensation shall be payable on and after the first day of the first month following completion of each period of creditable service upon which such compensation is based.

(Pub. L. 87–730, § 106(a), (b), (d), Oct. 2, 1962, 76 Stat. 694, 695; Pub. L. 88–454, § 104(b), Aug. 20, 1964, 78 Stat. 550; Pub. L. 90–57, § 105(g), July 28, 1967, 81 Stat. 143; Pub. L. 90–206, title II, § 214(n), Dec. 16, 1967, 81 Stat. 637; Pub. L. 91–656, § 4, Jan. 8, 1971, 84 Stat. 1952; Pub. L. 93–371, Aug. 13, 1974, 88 Stat. 436; Pub. L. 95–240, title II, § 205, Mar. 7, 1978, 92 Stat. 117; Pub. L. 95–391, title I, § 110(a), Sept. 30, 1978, 92 Stat. 774; Pub. L. 96–304, title I, § 107(b), July 8, 1980, 94 Stat. 890.)