RFIs 8-12pdf.pdf

Solicitation #W912BU-21-Q-0016 Thru October 19, 2021

Questions during solicitation

8.) Clause C316 of the solicitation reads as follows:

“A natural vent opening with motorized louver shall be provided on the aft side of the stack to exhaust heat. The motorized louver shall be automatically controlled with the respective port or starboard engine room exhaust fan being energized.”

Additionally, Clause C685 (Heating Ventilation & Air Conditioning), C (Engine Room Ventilation), 3 (Exhaust Fans) reads as follows:

“Exhaust fan(s) shall be provided and mounted, with gaskets, in the aft end of each engine room stack.”

Can USACE please confirm that there are to be two (2) distinct exhaust openings on the aft end of the stack(s), both with automatic motorized louvers, but only one incorporating an axial exhaust fan?

9.) Clause C685 (Heating Ventilation & Air Conditioning), G (Stack Ventilation Louvers) reads as follows:

“The contractor shall furnish and install exhaust louvers on the side of the stack. The exhaust louvers shall be a wind-drive rain, horizontal blade louver with integral Damper and blade seals, motorized actuator, and stainless steel insect screen.

Provisions shall be made for the automatic closure of the louvers upon activation of the fixed fire suppression system or the fire detection system.”

Can USACE please confirm that the subject side exhaust louvered openings are not to be equipped with an exhaust fan?

10.) Clause C685 (Heating Ventilation & Air Conditioning), C (Engine Room Ventilation), 2 (Supply Fans) reads as follows:

“Supply fan(s) shall be installed on the deckhouse sides or the upper deck with watertight cowling. The fans shall be connected to a plenum that terminates in the engine room.”

Additionally, Clause C685 (Heating, Ventilation & Air Conditioning), D (Upper Engine Room Ventilation), 2 (Supply Fans) reads as follows:

“Supply fan(s) shall be installed on the deckhouse sides or the upper deck with watertight cowling. The fans shall be connected to a plenum that terminates in the engine room.”

As the wording for both of these sections is identical, can USACE please confirm that only one supply air intake fan with ducting is required on both port/starboard sides of the main deckhouse (or both port/starboard extents of upper deck) to service both the main engine room and the upper engine room?

With regard to Questions 8 to 10, the SOW exhibits some degree of ambiguity regarding the intakes/exhausts fans/louvers requirements. Due to the large cutouts in the main deck to accommodate removal of the main engines, it stands to reason that the ventilation appurtenances meant to service the upper engine room will also service the lower engine room and vice versa, i.e. the exhaust fan on the aft end of the stack (meant to exhaust the main engine room) will invariably remove air from the upper engine room, and the exhaust fans on the upper deck meant to service the upper engine room will help ventilate the main engine room. As such we would treat the main engine room and upper engine room as a common space.

Can the USACE please provide clarification regarding the quantity of supply fans, exhaust fans, and louvered exhaust openings required for this space?

11.) Clause C685 ((Heating Ventilation & Air Conditioning), C (Engine Room Ventilation), 1 (Ventilation Calculations) reads as follows:

“If the generators are installed in this space, the ventilation system shall account for carrying away radiated heat of both generators operating at the engines’ maximum rating at the same time as well…If the generators are installed in this space, account fir their combustion air as well.”

However, Clause C685 (Heating Ventilation & Air Conditioning), F (Generator Engine Combustion Air) reads as follows:

“The contractor shall furnish and install a dedicated combustion air system for each Generator engine. The combustion air system for each generator engine shall be Consist of a dedicated ducting system and a double cell combustion air intake filter, size 1200, with weather protection and support legs.”

Can USACE please confirm that since the generator engines will have dedicated ducted exterior air supplies, it is not necessary to account for combustion air when determining the required machinery space ventilation capacity?

12.) We are requesting clarification pertaining to bulwarks on the Main Deck:

In C425, Section C, it says that “For the main deck level forward of the deckhouse perimeter protection, a Type C (USACE Safety Manual) non-tensioned railing system with five tiers shall be installed.”

In C460 Section D, it says “The VESSEL NAME, in Gothic letters, 10-inches high shall be cut from ¼-inch plate and shall be centered and seal-welded on the stern of the vessel, main deck bulwark, on centerline.”

In C669, Section B, it says “The main deck bulwark shall be designed with the necessary freeing ports to satisfy the ABS and USCG rules.”

What we would like clarification on is there supposed to be a combination of Bulwarks and railings on the main deck (railings at the sides and bulwarks forward and aft), or will bulwarks going around the entire main deck be satisfactory?

Answers:

8.) The stack(s) shall have one fan with automatic motorized louvers. The location to be determined by the contractor. An additional motorized louver is not required on the aft end.

9.) The stack louver(s) on the side are not required.

10.) The engine room and upper engine room can be considered the same space for the ventilation calculations. There shall be at least one supply fan and one exhaust fan in each of the stack(s).

11.) Since the generator engines shall have dedicated ducted exterior air supplied, it is not necessary to account for combustion air when determining the required machinery space ventilation capacity.

12.) There shall be no bulwark on the main deck. References to a bulwark in

Clauses C410, C415, C460 and C669 are in error. Clause C425, paragraph C is the correct requirement.

For the main deck level forward of the deckhouse, a Type C non-tensioned railing system with five tiers and removable stanchions shall be installed. Aft of the forward deckhouse bulkhead, a Type B tensioned railing system with three tiers and removeable stanchions shall be installed.