My intention is to familiarize people like me who are just starting to acquire knowledge about the ASHRAE Standard 90.1. Most of these items are done as part of the Plan & Spec and Design Build process; now they’re requirements. I strongly recommend that everyone in the HVAC Industry goes on the ASHRAE web site http://www.ashrae.org/technology/page/548 and clicks on the link for Standard 90.1. When the book opens click on the “page” button at the bottom and go to page 30. Page 30 through 55 deals with the mechanical systems minimum standards. The information is well organized and points us in the right direction for operating cost reduction strategies. If you’re a property owner, manager or facility engineer this is a small glimpse into big changes coming your way. Standard 90.1 mainly specifies building construction that will reduce the energy consumption of the mechanical systems.
6.1) this section spells out the general guidelines for compliance of new buildings, additions to an existing building, (unless the addition is served by existing systems) and alterations to existing systems. Direct replacement equipment and components including HVAC, A/C, economizer, duct and piping shall comply with sections 6.2 through 6.8. Exceptions found in section 6.1 include alterations that will not increase power consumption and replacement or alterations that require extensive revisions. Changing refrigerants, relocation of existing equipment or where there is insufficient space for modifications to duct and pipe are also exempt.
6.2) this section is used to determine if compliance is required for a project. This section offers two options moving forward, one is the simplified approach which will follow section 6.3. Section 6.3 would be the option of choice for upgrades and direct unit replacements for small existing buildings. The other is to follow section 6.4 which offers more options. 6.4 would be the option of choice for new construction or additions to the existing building.
6.3) this section begins with building specifics which are one and two story buildings with less than 25,000 ft². Each system must meet all the criteria. Basically a split system or package unit with a heat section and a DX cooling that is either an air cooled condenser or evaporative condensers that complies with section 6.8. The units will need an economizer and barometric relief that both comply with section 6.4. The equipment will need the controls specified in section 6.5. Basically to take the simplified approach you need meet the requirements of section 6.3, 6.5 and 6.8. There are 15 specific criteria in section 6.3 that need to be met as well as table 6.3.2 that can be used to minimize or eliminate the economizer. If all aspects of the building and equipment are met you can go straight to section 6.7 which is the submittal process. If all the criteria are not met you must follow the guidelines in section 6.4.
6.4) this section gives the system selection engineer or salesperson direction as to what rules apply to the proposed system. This section would be best described as the basis for design and equipment selection, if you have equipment type X; then you must meet conditions A, B, and C. It would work well as a question and answers program in a load calculation/equipment selection software package. This is the must read section of the standard 90.1 for everyone in the HVAC industry. It is 4 pages of material that will be used to ensure that the project will meet code in the near future.
6.5) this section details the specifications for heating/cooling changeover, economizer operation and building systems integration. The requirements that need to be met are VFD settings and minimums for fan motors and hydronic pumps. Others include the changeover deadband set points and decreased airflow set points. Section 6.5 also deals with the specific operation and set points of the system during heating, cooling, and dehumidification. It establishes the guidelines for exhaust air energy recovery, kitchen exhaust, and fume hood exhaust.
6.7) this section organizes the documentation requirements for the project submittals. The intention here is to make sure everyone associated with the project gets the documents that show that the mechanical requirements are met. Most of these are standard items that are commonly requested. The expanded information will now include listing a service provider, preventive maintenance schedules, and certified building commissioning.
6.8) this is the last mechanical equipment section and it’s the tables that organize the minimum efficiency requirements, standard ratings and operating conditions. It is clearly laid out and easy to follow by system type. For new equipment installations it will be easy since the equipment manufactures’ will be required to meet the minimum standards. For upgrade and modification work it will be a matter of documenting the existing equipment.
