#### § 116.415 Fire control boundaries.

(a) *Type and construction of fire control bulkheads and decks* —

(1) *Major hull structure.* The hull, structural bulkheads, columns and stanchions, superstructures, and deckhouses must be composed of steel or equivalent material.

(2) Bulkheads and decks—Bulkheads and decks must be classed as A-60, A-30, A-15, A-0, B-15, B-0, C, or C' based on the following:

(i) A-Class bulkheads or decks must be composed of steel or equivalent material, suitably stiffened and made intact with the main structure of the vessel, such as the shell, structural bulkheads, and decks. They must be so constructed that, if subjected to the standard fire test, they are capable of preventing the passage of smoke and flame for 1 hour. In addition, they must be so insulated with approved structural insulation, bulkhead panels, or deck covering so that, if subjected to the standard fire test for the applicable time period listed below, the average temperature on the unexposed side does not rise more than 139 °C (250 °F) above the original temperature, nor does the temperature at any one point, including any joint, rise more than 181 °C (325 °F) above the original temperature:

| A-60 Class | 60 minutes |
| A-30 Class | 30 minutes |
| A-15 Class | 15 minutes |
| A-0 Class | 0 minutes |

(ii) Penetrations in A-Class fire control boundaries for electrical cables, pipes, trunks, ducts, etc. must be constructed to prevent the passage of flame and smoke for one hour. In addition, the penetration must be designed or insulated so that it will withstand the same temperature rise limits as the boundary penetrated.

(iii) B-Class bulkheads and decks must be constructed of noncombustible materials and made intact with the main structure of the vessel, such as shell, structural bulkheads, and decks, except that a B-Class bulkhead need not extend above an approved continuous B-Class ceiling. They must be so constructed that, if subjected to the standard fire test, they are capable of preventing the passage of flame for 30 minutes. In addition, their insulation value must be such that, if subjected to the standard fire test for the applicable time period listed below, the average temperature of the unexposed side does not rise more than 139 °C (250 °F) above the original temperature, nor does the temperature at any one point, including any joint, rise more than 225 °C (405 °F) above the original temperature:

| B-15 Class | 15 minutes |
| B-0 Class | 0 minutes |

(iv) Penetrations in B-Class fire control boundaries for electrical cables, pipes, trunks, ducts, etc. must be constructed to prevent the passage of flame for 30 minutes. In addition, the penetration must be designed or insulated so that it will withstand the same temperature rise limits as the boundary penetrated.

(v) C-Class bulkheads and decks must be composed of noncombustible materials.

(vi) C′-Class bulkheads and decks must be constructed of noncombustible materials and made intact with the main structure of the vessel, such as shell, structural bulkheads, and decks, except that a C′-Class bulkhead need not extend above a continuous B-Class or C′-Class ceiling. C′-Class bulkheads must be constructed to prevent the passage of smoke between adjacent areas. Penetrations in C′-Class boundaries for electrical cables, pipes, trunks, ducts, etc. must be constructed so as to preserve the smoke-tight integrity of the boundary.

(vii) Any sheathing, furring, or holding pieces incidental to the securing of structural insulation must be approved noncombustible material.

(b) *Bulkhead requirements.* Bulkheads between various spaces must meet the requirements of Table [116.415(b)](/on/2024-09-23/title-46/section-116.415#p-116.415(b)).

Table [116.415](/on/2024-09-23/title-46/section-116.415) (b)—Bulkheads

| Spaces | (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | (13) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Control Space (1) | B-0 | A-0 | A-0 | A-0 | A-15 | A-60 | A-60 | A-0 | A-60 | A-60 | A-60 | A-0 | A-0 |
| Stairway (2) | | A-04 | A-0 | A-0 | A-0 | A-60 | A-60 | A-0 | A-15 | A-15 | A-15 | A-0 | A-0 |
| Corridor (3) | | | C | A-0 | B-0 | B-0 | A-0 | B-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Embarkation Station (4) | | | | C | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | C'1 | C |
| Low Risk Accommodation (5) | | | | | B-0 | B-15 | B-15 | B-02 | A-15 | A-15 | A-15 | A-0 | A-0 |
| High Risk Accommodation (6) (≤50 sq. m.) | | | | | | B-15 | A-30 | B-02 | A-60 | A-60 | A-60 | A-0 | A-0 |
| High Risk Accommodation (7) (>50 sq. m.) | | | | | | | A-60 | B-02 | A-60 | A-60 | A-60 | A-0 | A-0 |
| Low Risk Service Spaces (8) | | | | | | | | C | A-0 | A-0 | A-0 | A-0 | A-0 |
| High Risk Service Spaces (9) | | | | | | | | | C3 | A-0 | A-0 | A-0 | A-0 |
| Machinery Spaces (10) | | | | | | | | | | C | A-0 | A-0 | A-0 |
| Cargo Spaces (11) | | | | | | | | | | | A-0 | A-0 | A-0 |
| Auxiliary Machinery spaces, voids, fuel and water tanks (12) | | | | | | | | | | | | C'1 | C'1 |
| Open decks (not safety areas) (13) | | | | | | | | | | | | | C |
| | | | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 Boundaries of fuel tanks, auxiliary machinery spaces, and voids that contain a fire load in excess of 2.5kg/m2 (0.5 pounds per square foot) must be minimum A-0 Class construction. | | | | | | | | | | | | | |
| 2 Toilet space boundaries may be reduced to C′-Class. | | | | | | | | | | | | | |
| 3 C-Class bulkheads may be used between two similar spaces, such as between two storerooms; however, an A-0 Class bulkhead shall be used between two dissimilar spaces, such as a storeroom and a workshop. | | | | | | | | | | | | | |
| 4 Separation is not required within a single stairtower. A-0 construction is required between two distinct stairtowers. | | | | | | | | | | | | | |

(c) *Deck requirements.* Decks between various spaces must meet the requirements of Table [116.415(c)](/on/2024-09-23/title-46/section-116.415#p-116.415(c)), except that where linings or bulkhead panels are framed away from the shell or structural bulkheads, the deck within the void space so formed need only meet A-0 Class requirements.

Table [116.415](/on/2024-09-23/title-46/section-116.415)(c)—Decks

| Space Above | (1) | (2) | (3) | (4) | (5) | (6) | (7) | (8) | (9) | (10) | (11) | (12) | (13) |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Space Below: | | | | | | | | | | | | | |
| Control Space (1) | A-0 | A-0 | A-15 | A-0 | A-0 | A-15 | A-30 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Stairway (2) | A-0 | C | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Corridor (3) | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-15 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Embarkation Station (4) | A-0 | A-0 | A-0 | C | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | C'1 | C |
| Low Risk Accommodation (5) | A-15 | A-15 | A-0 | A-0 | A-0 | A-0 | A-15 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| High Risk Accommodation(6) (≤50 sq. m.) | A-60 | A-60 | A-30 | A-15 | A-0 | A-30 | A-60 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| High Risk Accommodation (7) (>50 sq. m.) | A-60 | A-60 | A-60 | A-30 | A-15 | A-60 | A-60 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Low Risk Service Spaces (8) | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| High Risk Service Spaces (9) | A-60 | A-30 | A-30 | A-30 | A-15 | A-60 | A-60 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Machinery Spaces (10) | A-60 | A-60 | A-60 | A-30 | A-15 | A-60 | A-60 | A-0 | A-0 | C | A-0 | A-0 | A-0 |
| Cargo Spaces (11) | A-60 | A-30 | A-30 | A-30 | A-15 | A-60 | A-60 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 |
| Auxiliary Machinery Spaces, voids, fuel and water tanks (12) | A-0 | A-0 | A-0 | C'1 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | C'1 | A-01 |
| Open decks (not safety areas) (13) | A-0 | A-0 | A-0 | C | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-0 | A-01 | C |
| | | | | | | | | | | | | | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 Boundaries of fuel tanks, auxiliary machinery spaces, and voids that contain a fire load in excess of 2.5 kg/m2 (0.5 pounds per square foot) must be minimum A-0 Class construction. | | | | | | | | | | | | | |

(d) *Main vertical zones.*

(1) The hull, superstructure, and deck houses of a vessel, except for a vehicle space on a vehicle ferry, must be subdivided by bulkheads into main vertical zones which:

(i) Are generally not more than 40 meters (131 feet) in mean length on any one deck;

(ii) Must be constructed to:

(A) The greater of A-30 Class or the requirements of [paragraph (b)](/on/2024-09-23/title-46/section-116.415#p-116.415(b)) of this section, or;

(B) Minimum A-0 Class where there is a Type 8, 12 or 13 space on either side of the division; and

(iii) May have small horizontal steps, if the steps:

(A) Do not exceed 20% of the mean length of the main vertical zone or 8 meters (26 feet), whichever is smaller; and

(B) Must be constructed to A-60 Class, or minimum A-0 Class where there is a Type 8, 12 or 13 space on either side of the division.

(iv) May be extended to a maximum mean length of 44 meters (144 feet) on each deck by the Commanding Officer, Marine Safety Center provided the maximum distance between the furthermost points of the bulkheads bounding the main vertical zone also does not exceed 44 meters (144 feet).

(2) Vehicle decks on a vehicle ferry must be subdivided. Where main vertical zones are impractical due to the vehicle carrying configuration, main horizontal zones may be provided. The decks bounding such a zone must be of at least A-30 construction or meet the requirements of [paragraph (c)](/on/2024-09-23/title-46/section-116.415#p-116.415(c)) of this section, whichever is greater.

(e) *Draft stops.* In concealed spaces above ceilings and between linings and the shell of a vessel, draft stops must be fitted not more than 13.7 meters (45 feet) apart in the horizontal direction and at each deck level in the vertical direction unless otherwise permitted in paragraph (f). Draft stops must be of at least B-Class construction and be fitted in a vertical position.

(f) On vessels with no overnight passenger accommodations, draft stops are not required above/around large public spaces provided all of the following conditions are met:

(1) The space in question is surrounded by A-Class divisions or extends to the outer shell of the vessel.

(2) The space in question is open and unobstructed such that a fire in any part of the space will quickly be discovered.

(3) The area above the ceiling is easily accessible from below for fire fighting purposes.

[CGD 85-080, [61 FR 900](https://www.federalregister.gov/citation/61-FR-900), Jan. 10, 1996; [61 FR 20556](https://www.federalregister.gov/citation/61-FR-20556), May 7, 1996; [61 FR 24464](https://www.federalregister.gov/citation/61-FR-24464), May 15, 1996, as amended at [62 FR 51348](https://www.federalregister.gov/citation/62-FR-51348), Sept. 30, 1997; USCG-1998-4442, [63 FR 52191](https://www.federalregister.gov/citation/63-FR-52191), Sept. 30, 1998]