From lighting upgrades to custom coils on a factory chiller, explore specifics while absorbing the message to increase team integration earlier in the process. Update: Standard no longer free. There are also mandatory provisions that building envelopes have to abide by which are insulation, fenestration and doors, and air leakage. Each section of the building envelope, Roof, Walls, and Floor have different requirements for each of the mandatory provisions.
The HVAC system has many different requirements that have to be met. This is because there are many types of HVAC systems each with different requirements. The HVAC section has the most requirements because there are so many different types of systems. There are systems that can not be used and things that systems must have to meet the requirements.
Hot water systems must go through a load calculation before they are installed. Each system must meet the manufactures sizing guidelines. The pipes that hold the hot water need to be insulated and there are certain insulation requirements for each system type and piping material.
There are many controls that hot water systems need and each control has a different requirement. These include are temperature controls, temperature maintenance controls, outlet temperature controls, and circulation pump controls.
There are also requirements for pool heaters, pool covers, and heat traps for heated pools. One exception is that this control is not required if the system requires an ERV by section 6. This technique is allowed under exception a2 in 6.
So for those looking to exceed the minimum requirements, this is one place to do it. Ventilation Air Intake Exhaust Relief non-motorized1 motorized non-motorized1 motorized 20 4 20 4 20 10 20 10 less than 3 stories not allowed 10 20 10 3 or more stories not allowed 10 not allowed 10 less than 3 stories not allowed 4 20 4 3 or more stories not allowed 4 not allowed 4 Climate Zone 1,2 any height 3 any height 4, 5b, 5c 5a, 6, 7, 8 1 Dampers smaller than 24 in.
Addendum CB Exhaust air energy recovery. Energy recovery ventilators ERVs are justifiable in a lot more situations, now that energy costs have risen and the component costs have come down. There are three intersecting thresholds: climate, a percentage of outdoor air, and the supply airflow rate see Table 4. There is no ERV requirement, for any size system in any climate, if below 30 percent outdoor air at full design airflow.
There are 10 exceptions to the ERV requirement, related to situations where exhaust heat recovery is not economical or practical.
Airside h Where the largest source of air exhausted at a single location at the building exterior is less than 75 percent of the design outdoor airflow rate. Zone-level demand-controlled ventilation DCV. As of As discussed in an earlier newsletter2, several techniques are suitable for this control, depending on the space type and use.
In addition to single-zone VAV, there are several new or modified requirements for airside controls. Supply air reset. A requirement for supply air temperature SAT reset was removed from Part of the ambivalence The goal is to set up the SAT reset strategy so that it gradually resets to full reset at a point when most zones have minimal cooling loads, and the additional fan energy will not overwhelm the reheat savings.
A simple approach for doing this was mentioned in a recent newsletter3. Table 4. A previous engineers newsletter1 explains this control in detail. Overhead heating temperature limit.
This minimizes temperature stratification and short circuiting to increase zone air distribution effectiveness. The new dual maximum control stratgey may be used so that airflow can be increased in heating mode. This change is aimed at avoiding the need to increase zone outdoor airflow due to temperature stratification when supplying hot air from ceiling-mounted diffusers and returning through ceiling-mounted grilles.
A new option was added for the maximum amount of air that can be cooled and then reheated Figure 2. The new control option requires that primary airflow be reduced to 20 percent of design cooling airflow, but then allows primary airflow to be modulated up to a maximum of 50 percent of design airflow for heating. This allows heating to be accomplished with a lower discharge-air temperature, which improves zone air-distribution effectiveness. Addendum H Figure 2. Additionally, the colder supply-air temperature allows the system to provide sufficiently dry air to the zones, improving part-load dehumidification.
This blanket exception was removed, and a new section on laboratory exhaust specifies the effectiveness and control needed to make sure that these zones are not maintained at constant flow when the air is not needed for pressure control. As previously mentioned on page 2 for packaged systems effective January , and as of January for chilled water systems, variable-airvolume fan control is required for single-zone systems.
This change requires either two-speed motors or variablespeed drives on the supply fan s , and may invoke the need for discharge air temperature sensors and outdoor airflow measurement.
Addendum N Fan power limitation. When the single-zone VAV change occurred, the Singlezone VAV systems are required to use the more stringent constant volume fan power limit. Allowances for exhaust systems were previously poorly defined. This created a hardship for several types of buildings and specifically laboratories, hospitals, and vivariums. Waterside Two-position valves in water-cooled unitary products. Condenser water flow for unitary systems can only be variable if at least a two-position valve is included at the unit, to shut off water flow when the unit is turned off.
Since , water-source heat pumps have been required to have these valves; now this is a requirement for watercooled unitary air conditioners also. For water-cooled unitary systems of greater than 5 hp, a VFD is required on the pump motor, or it must have similar performance. Addendum AK. Variable-flow and variable-speed pumping.
In hydronic systems other than water-cooled unitary systems, if the system power is greater than 10 hp, a VFD is required on the pump motor, or it must have similar performance.
This is a dramatic change. In the past, at 10 hp for the system, the system had to have, at minimum, two-way valves and ride the pump curve. At 50 hp per pump, with at least ' of head, a VFD was required. Now, when individual pumps are 5 hp or more, and the system power is at least 10 hp, VFD-like performance is required. Addendum AK Service water booster systems. Pumps are often installed in service water systems aka domestic hot water to boost the pressure at a specific point in the system.
Downstream of that booster system, Pressure must be measured and pump operation varied to better follow the load. And pump s must be shut off when no service water flow is required. With all the new requirements for variable speed pumping, it follows that There are two main requirements: the differential pressure DP setpoint can be no more than the DP that corresponds to percent of the design flow rate, and the DP setpoint has to be reset until one valve is nearly wide open.
Addendum AK Pipe insulation. Chilled-water piping insulation requirements have modest changes, but hot water and especially steam pipes have significant upgrades.
There are exceptions: for example, when pipes are in the interior walls between conditioned spaces. And if non-metallic pipe is used, and it's greater than schedule 80 thickness, you may reduce insulation thickness to an equivalent heat transfer per linear foot. There are adjustments for buried pipe. See Table 1. Outdoor Air This change limits the amount of frictional loss that the system pumps must overcome.
System design delta T impacts which pipe sizes are permitted. For example, if you really want 6-inch and not 8-inch pipes, you may have to increase the delta T reduce the flow rate. For pipe sizes larger than 12', you adhere to a maximum velocity. Standard This is similar to the requirement for load calculations. Addendum V There are four main topics for outdoor air system design and control: economizers, energy recovery ventilators, dampers, and ventilation controls. A sweeping addendum changed economizer requirements.
That is, economizers are now economically justified in most climate zones. Two exceptions are climate zones 1a and 1b, which include the areas highlighted in Figure 1 and other very hot climates worldwide. Addendum CY Smaller systems will need economizers as well. Some jurisdictions have interpreted this as applying if the entire system is greater than 4.
This requirement could be satisfied by either a water or air economizer. One way that more climates were justified is by dropping the exceptions for integrated economizing.
Some sections have mandatory provisions, simplified approaches, or trade-off opportunities. In the performance approach, a baseline Energy Cost Budget ECB is established, based on the building size and program.
This baseline ECB is established using building performance simulation to model a building with the same size and program as the project building, built according to the prescriptive requirements of ASHRAE The ECB is expressed in units of dollars.
A building performance simulation is then performed on the proposed building design. The proposed energy cost budget must be less than or equal to the baseline energy cost budget to achieve compliance. The performance approach is also used to demonstrate design energy efficiency, often expressed as percent better than ASHRAE Standard Most states apply the standard or equivalent standards for all commercial buildings.
Others apply the standard or equivalent standards for all government buildings. There are some states that use other energy conservation standards for all commercial buildings and some other states that use a combination of the ASHRAE A few states do not apply any energy conservation standards for their government and commercial buildings. Current status of adoption into energy codes is tracked by the Building Codes Assistance Project.
It is frequently used as a baseline for comparison during energy retrofit projects or any project that employs building performance simulation.
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