Code Reference(s):

NFC20, Div. B 5.6.4.3.

Subject:

Additional Requirements for EMTC

Title:

Revised measures for protection of EMTC during construction

Description:

This proposed change mirrors the proposed changes contained in PCF1872 and PCF1879, currently undergoing public review as a part of their implementation into the National Model Codes. This proposed change describes revisions to Article 5.6.4.3.-2020 addressing the minimum requirements and exceptions for encapsulation of mass timber elements during construction in buildings permitted to be of encapsulated mass timber construction.

*Note: this proposed change was provided by the Joint Task Group – Harmonized Variations for Mass Timber*

Related Proposed Change(s):

PCF01, PCF02, PCF03, PCF04, PCF05

PROPOSED CHANGE UNDER PCF1872 & PCF1879 (FOR INCLUSION INTO NFC 2025)

5.6.4.3.Protective Encapsulation and Fire Protection

1) Except as provided in Sentences (2)and (3),Sentences (2) to (4) and (6)-2025,to address safety during construction, a protective encapsulation material or an assembly of materials providing an encapsulation rating of not less than 25 min, as determined in accordance with Sentence 3.1.6.5.(1) of Division B of the NBC, shall be installed

a) such that not more than 20% of the area of the underside of each mass timber floor assembly on each storey is exposed during construction,

b) on the interior side of stairways required by Sentence 5.6.3.7.(3) and of vertical service spaces where the enclosures are constructed of mass timber elements,

c) on each face of solid lumber or mass timber partitions not less than 38 mm thick and on each face of partitions containing wood framing as permitted by Article 3.1.6.15. of Division B of the NBC, and

d) such that not more than 35% of the total the exposed surfacearea of structural mass timber walls within the storeyis exposed during construction.does not exceed

i) the aggregate exposed surface area of the suite stated in Sentence 3.1.6.4.(5) of Division B of the NBC, or

ii) 35% of the total wall area of the perimeter of the storey (see Note A-5.6.4.3.(1)(d)).

(See Note A-5.6.4.3.(1).)

2) Except as provided in Sentence (5)-2025, a protective encapsulation material or assembly of materials need not be installed as described in Clause (1)(a), provided

a) penetrations or openings through the floor assembly on any storey are

i) protected with a firestop conforming to Sentence 3.1.9.1.(1) of Division B of the NBC,

ii) filled with noncombustible insulation that is supported in place, or

iii) protected, from the top of the floor assembly, with a single layer of not less than 12.7 mm thick Type X gypsum board mechanically fastened to not less than 12.7 mm thick plywood or OSB with the gypsum board facing the penetration (see Note A-5.6.4.3.(2)(a)-2025),

b) joints located in a horizontal plane between the floor and an exterior wall on any storey are

i) protected with a firestop conforming to Sentence 3.1.8.3.(4) of Division B of the NBC, or

ii) filled with noncombustible insulation that is supported in place,

c) a standpipe system is installed in accordance with Articles 5.6.1.6. and 5.6.4.2., and is provided with hose stations for occupant use that are equipped with a hose line having

i) a diameter of either 25 mm or 38 mm, and

ii) a length sufficient to cover all parts of the storey with a hose stream of not less than  5 m (see Note A-5.6.4.3.(2)(c)-2025), and

d) a fire watch is conducted on all storeys

i) at intervals of not more than 1 h when workers are present in the building, and

ii) not less than 1 h after workers leave the building (see Note A-5.6.4.3.(2)(d)-2025).

3) Except as provided in Sentence (4)-2025, a protective encapsulation material or assembly of materials need not be installed as described in Clauses (1)(a), (c), and (d), provided an automatic sprinkler system

a) is progressively installed during construction in accordance with NFPA 13, “Standard for the Installation of Sprinkler Systems” (see Note A-5.6.4.3.(3)(a)), and

b) is in an operable condition at all times on any storey where it is not actively being worked on, until the automatic sprinkler system is completed.

2)4)Not more than tThe four uppermost contiguousstoreysare permitted to be unprotected as required byneed not conform to the requirements ofSentence (1) or the conditions of Sentence (3)-2025during construction.

5) The first four storeys need not conform to the conditions of Sentence (2)-2025 during construction, until the ceiling assembly of the fifth storey is installed. (see Note A-5.6.4.3.(5)-2025)

3)6)The encapsulation material or assembly of materials used to meet the requirements of Sentence (1) is permitted to consist of a single layer of Type X gypsum board not less than 12.7 mm thick conforming to Clauses 3.1.6.6.(4)(a) and (c)-2025 of Division B of the NBCClauses 3.1.6.6.(2)(a), (c), and (d) of Division B of the NBC.

Note A-5.6.4.3.(1)(d)-2025 The intent of Clause 5.6.4.3.(1)(d) is that the maximum area of mass timber walls that is permitted to be exposed in the finished building also be permitted to be exposed during construction. In the calculation of the total wall area of the perimeter of a suite or storey, the area of any wall openings, such as doors or windows, are included.

Note A-5.6.4.3.(2)(a)-2025 Until permanent protection is provided, the fire protection of the penetrations or openings through the floor assembly can be temporary. Beyond those described in Clause 5.6.4.3.(2)(a)-2025, other forms of protection should have a noncombustible or other protective layer that will resist fire for a minimum of 30 min. Furthermore, any such protective layer should be structurally adequate over the penetrations or openings for the safety of occupants.

The fire protection of large penetrations or openings through floor assemblies, such as openings associated with convenience stairs, elevators or interconnected floor spaces, should address additional fire protection considerations, including structural support.

Note A-5.6.4.3.(2)(c)-2025 The length of hose should be sufficient to allow for adequate nozzle pressure and will depend on the chosen hose diameter. Typically, 38 mm diameter hose should have a length of not more than 30.5 m.

If construction reaches a height at which the public waterworks system can no longer provide the required flow and pressure, a temporary or permanent fire pump must be installed to adequately protect the uppermost storey of the building, unless the fire safety plan specifies an alternative approach that is permitted by the authority having jurisdiction.

Note A-5.6.4.3.(2)(d)-2025 The person conducting the fire watch should be familiar with all fire safety features of the building, including the fire safety plan, as provided in conformance with Section 2.8.

Note A-5.6.4.3.(3)(a)-2025 Even though NFPA 13, “Standard for the Installation of Sprinkler Systems”, does not include specific provisions for installation of sprinklers during construction, it is expected that the requirements of NFPA 13 will be fully implemented as appropriate for the conditions that exist in the building under construction.

Note A-5.6.4.3.(5)-2025 It is intended that all storeys meet the conditions of Clause 5.6.4.3.(2)-2025 once the ceiling assembly of the fifth storey has been installed.

ADDITIONAL PROPOSED CHANGE UNDER THIS PCF

5.6.4.1.Application

1) This Subsection applies to buildings or parts thereof conforming to Article 3.2.2.48.,or 3.2.2.57. or 3.2.2.93.of Division B of the NBC that are under construction.

5.6.4.3.Protective Encapsulation and Fire Protection

1) Except as provided in Sentences (2) to (6), for buildings more than 6 storeys in building height, to address safety during construction, a protective encapsulation material or an assembly of materials providing an encapsulation rating of not less than 25 min, as determined in accordance with Sentence 3.1.6.5.(1) of Division B of the NBC, shall be installed

a) such that not more than 20% of the area of the underside of each mass timber floor assembly on each storey is exposed during construction,

b) on the interior side of stairways required by Sentence 5.6.3.7.(3) and of vertical service spaces where the enclosures are constructed of mass timber elements,

c) on each face of solid lumber or mass timber partitions not less than 38 mm thick and on each face of partitions containing wood framing as permitted by Article 3.1.6.15. of Division B of the NBC, and

d) such that the exposed surface area of structural mass timber walls within the storeydoes not exceed

i) the aggregate exposed surface area of the suite stated in Sentence 3.1.6.4.(5) of Division B of the NBC, or

ii) 35% of the total wall area of the perimeter of the storey (see Note A-5.6.4.3.(1)(d)).

(See Note A-5.6.4.3.(1).)

2) Except as provided in Sentence (5)(6), floor assemblies in a building or part of a building permitted by Article 3.2.2.93. to have a 0 min encapsulation rating need not be encapsulated in accordance with Clause (1)(a) and (d), provided

a) penetrations or openings through the floor assembly on any storey are

i) protected with a firestop conforming to Sentence 3.1.9.1.(1) of Division B of the NBC,

ii) filled with noncombustible insulation, or

iii) protected, from the top of the floor assembly, with a single layer of not less than 12.7 mm thick Type X gypsum board mechanically fastened to not less than 12.7 mm thick plywood or OSB with the gypsum board facing the penetration (see Note A-5.6.4.3.(2)(a) and (3)(a)),

b) joints located in a horizontal plane between the floor and an exterior wall on any storey are

i) protected with a firestop conforming to Sentence 3.1.8.3.(4) of Division B of the NBC, or

ii) filled with noncombustible insulation that is supported in place.

c) a standpipe system is installed in accordance with Articles 5.6.1.6. and 5.6.4.2., and is provided with hose stations for occupant use that are equipped with a hose line having a

i) a diameter of either 25 mm or 38 mm, and

ii) length sufficient to cover all parts of the storey assuming a hose stream of not greater than 5 m (see Note A-5.6.4.3.(2)(c) and (3)(c)), and

d) a fire watch is conducted on all storeys

i) at intervals of not more than 1 h when workers are present in the building, and

ii) not less than 1 h after workers leave the building (see Note A-5.6.4.3.(2)(d) and (3)(d)).

3) Except as provided in Sentence (6), floor assemblies in a building or part of a building constructed in accordance with Article 3.2.2.48 or 3.2.2.57 or permitted by Article 3.2.2.93. to have a 50 min or 70 min encapsulation rating need not be encapsulated in accordance with Clause (1)(a), provided

a) penetrations or openings through the floor assembly on any storey are

i) protected with a firestop conforming to Sentence 3.1.9.1.(1) of Division B of the NBC,

ii) filled with noncombustible insulation, or

iii) protected, from the top of the floor assembly, with a single layer of not less than 12.7 mm thick Type X gypsum board mechanically fastened to not less than 12.7 mm thick plywood or OSB with the gypsum board facing the penetration (see Note A-5.6.4.3.(2)(a) and (3)(a)),

b) joints located in a horizontal plane between the floor and an exterior wall on any storey are

i) protected with a firestop conforming to Sentence 3.1.8.3.(4) of Division B of the NBC, or

ii) filled with noncombustible insulation that is supported in place.

c) a standpipe system is installed in accordance with Articles 5.6.1.6. and 5.6.4.2., and is provided with hose stations for occupant use that are equipped with a hose line having a

i) a diameter of either 25 mm or 38 mm, and

ii) length sufficient to cover all parts of the storey assuming a hose stream of not greater than 5 m (see Note A-5.6.4.3.(2)(c) and (3)(c)), and

d) a fire watch is conducted on all storeys

i) at intervals of not more than 1 h when workers are present in the building, and

ii) not less than 1 h after workers leave the building (see Note A-5.6.4.3.(2)(d) and (3)(d)).

3)4)Clauses (1)(a), (c), and (d) do not apply where an automatic sprinkler system

a) is progressively installed during construction in accordance with NFPA 13, “Standard for the Installation of Sprinkler Systems” (see Note A-5.6.4.3.(3)(a)), and

b) is in an operable condition at all times on any storey where it is not actively being worked on, until the automatic sprinkler system is completed.

4)5)The four uppermost storeys need not conform to Sentence (1)during construction.

5)6)The first four storeys need not conform to Clause (1)(a) during construction, until the ceiling assembly of the fifth storey is installed. (see Note A-5.6.4.3.(5))

6) The encapsulation material or assembly of materials used to meet the requirements of Sentence (1) is permitted to consist of a single layer of Type X gypsum board not less than 12.7 mm thick conforming to Clauses 3.1.6.6.(4)(a) and (c) of Division B of the NBC.

Note A-5.6.4.3.(2)(a)and (3)(a)The fire protection of large penetrations or openings through floor assemblies, such as openings associated with convenience stairs, elevators or interconnected floor spaces, should address additional fire protection considerations, including structural support.

Until permanent protection is provided, the fire protection of the penetrations or openings through the floor assembly can be temporary. Beyond those described in Clause 5.6.4.3.(2)(a), other forms of protection should have a noncombustible or other protective layer that will resist fire for a minimum of 30 min. Furthermore, any such protective layer should be structurally adequate over the penetrations or openings for the safety of occupants.

Note A-5.6.4.3.(2)(c)and (3)(c)The length of hose should be sufficient to allow for adequate nozzle pressure and will depend on the chosen hose diameter. Typically, 38 mm diameter hose should have a length of not more than 30.5 m. If construction reaches a height at which the public waterworks system can no longer provide the required flow and pressure, a temporary or permanent fire pump must be installed to adequately protect the uppermost storey of the building, unless the fire safety plan specifies an alternative approach that is permitted by the authority having jurisdiction.

Note A-5.6.4.3.(2)(d) and (3)(d)The person conducting the fire watch should be familiar with all fire safety features of the building, including the fire safety plan, as provided in conformance with Section 2.8.

Note A-5.6.4.3.(3)(a)(4)(a) Even though NFPA 13, “Standard for the Installation of Sprinkler Systems”, does not include specific provisions for installation of sprinklers during construction, it is expected that the requirements of NFPA 13 will be fully implemented as appropriate for the conditions that exist in the building under construction.

Note A-5.6.4.3.(5)(6) It is intended that all storeys meet the requirements of Clause 5.6.4.3.(1)(a) or Sentence 5.6.4.3.(2) once the ceiling assembly of the fifth storey has been installed.