Laserfiche WebLink
` , I <br /> �,; <br /> i.j i!'�� <br /> DlBBE�� �I�GI�JEERS !NC � . <br /> December 28, 2017 <br /> duoTEC <br /> Attn: Duong Cun <br /> 650 S Orcas St, Ste 104 �,"�CC`�`�, ;�' ;'� �- <br /> Seattle, WA 98108 ��� �`i""" ` '� ' <br /> �:;.. , <br /> �; <br /> JA�J �� + ; ; : <br /> Re: Community Transit HVAC Replacement; DEI Project: 17-609 , %AR? ' ' ` <br /> � �_�% <br /> 2300 Kasch Park Rtl, Everett,WA 98204 �-���.�, �; � , <br /> �f� �.�`�,. � r <br /> f�errni�� ��;r��i�.��,,. <br /> Dear Mr. Cun: ' <br /> Dibble Engineers, Inc. (DEI)visited the Community Transit Center in Everett, WA located at the address above to <br /> review the existing roof framing for builtling B and building D.The primary concern discussed during the time of the <br /> site visit was to review the existing framing and to ensure that the existing roof framing is atlequate to support new <br /> HVAC units. <br /> Building B has 2, 5,and 10 ton HVAC units to be replaced. Existing roof framing consists of premanufacturetl wootl <br /> trusses at 24"or 48"on center.Trusses have 24"spacing at HVAC locations and 48"spacing otherwise. The trusses <br /> are supported by exterior bearing walls and an interior glulam beam. Please see the Building B Plan attachetl for <br /> further clarification. DEI has reviewed the new and existing HVAC unit weights and has determined that the design <br /> load demantl on the roof trusses and glulam beam increases by less than 5%due to the new units. Therefore, per <br /> IEBC 403.3, no retrofits are required. Each new unit is to be placed on a curb adapter(max weight=200 pountls), <br /> which will attach to the existing curb per manufacturer.The HVAC units will attach to the curb adapters per <br /> manufacturer(minimum#10 screw at 6"on center each side). <br /> Builtling D has an existing 8 ton unit to be replaced. Also,an existing 2 ton unit is to be removed antl capped per <br /> duoTEC. Existing roof framing consists of full span wood roof trusses at 48" on center. Please see building D plan <br /> attachetl for further clarification. The existing unit weighs approximately 1350 pountls, while the new unit weighs <br /> 1035 pounds.The new unit will be placetl on a new curb adapter(max weight=200 pountls). Per IEBC 403.3,the <br /> demand on the roof framing decreases,therefore no retrofits are requiretl.The new unit is to be placed on a curb <br /> adapter,which will attach to the existing curb per manufacturer. The HVAC unit will attach to the curb adapter per <br /> manufacturer(minimum#10 screw at 6"on center each side). _ <br /> � ! "� _ � ' `�i = � � �� , oa � o ��� <br />