By Alex Rippere
In a city that lived with the same ossified building code for 40 years before joining the rest of the country and adopting semi-regular revisions to the International Building Code as its local code, the pace of energy code changes has accelerated to breakneck speed. We are on the hook for another energy code change next year and, like the New York City Energy Conservation Code (NYCECC) 2016, the “new” NYCECC will go well beyond the vanilla provisions of the International Energy Conservation Code (IECC) 2018 it is based on.
In part, this radical rewrite is due to the fact that, per Local Law 32 of 2018, the new NYCECC will be based on a “stretch” version of the new state energy code. And if the state fails to enact the stretch code? Then, the city is obliged to investigate ways to make the IECC more stringent before enacting the new NYCECC.
What Is a “Stretch Code” Anyway?
A “stretch code” is an optional code standard that bridges the rule gaps between an existing code set and a future proposed code set. One reason why the state wants to enact a stretch code is to get the industry used to new code standards that exceed what even the latest version of the IECC 2018 has on offer. While the state will eventually move to the IECC 2018, designers will have the option to design under the stretch code, with an eye towards future code standards that national code entities haven’t even published yet.
New York City, by law, must always meet or beat the state energy code, and the city, as we all know, has a keen eye on keeping buildings as green as possible. So rather than make a handful of adjustments to the state code like last time, the city wants to adopt the state stretch code as its local standard. This move will make standards that are optional outside the five boroughs mandatory within them.
Now, this aggressive stance would not be that painful in the long run if putting the city on a more cutting-edge standard might avoid an energy code revision every three years, giving the industry more time to adjust. However, per Local Law 32, city energy code revisions will remain on a three-year cycle so New York City will always do its best to stay greener than the rest of the country [§28-1001.3.3 of the City Administrative Code, as enacted by Local Law 32]. The stage is now set for the 2019 and 2022 NYCECCs.
A Sneak Preview
The draft version of the state stretch code offers a glimpse of what shape the 2019 NYCECC could take, and it looks like the biggest changes will affect building envelope requirements. Some key takeaways:
- We’ll need more continuous insulation—in some cases, lots of it. Roofs will need R-35 instead of the R-30 insulation they can now install (about 7” of blue foam insulation above the deck). Mass walls will need R-11.4 or R-13.3 instead of R-9.5 or R-11.4, depending on the occupancy of the building. Metal-framed steel stud walls and curtain walls will need twice the continuous insulation on the face of the studs or curtain-wall framing, at R-15.6 as opposed to just R-7.5 now. Floors provided over unconditioned space, like the cantilevered slabs so popular on New York City buildings recently, will need R-15 or R-16.7 instead of R-10 or R-10.4, depending on the occupancy of the building. These changes come from revisions to Table C402.1.3, which mandates minimum insulation requirements. The maximum assembly conductivity (U-factor) option allowed under the revised Table C402.1.4 provides no relief either, as it has been adjusted almost across the board to require assemblies to hit lower U-factors than currently mandated.
- Fenestration requirements under Table C402.4 got about 5% more stringent, and must also achieve lower U-factors than they did under NYECC 2016. Further note: Even Solar Heat Gain Coefficient (SHGC) took a hit, with the maximum permitted value lowered to 0.35 from 0.40, meaning windows have to keep out more of the high-energy sunlight that brings heat into a building.
Further, the stretch code carries some key changes to power and lighting requirements under section C405, many of which are carried over from ASHRAE 90.1 Sections 8 and 9. These changes include:
- Exit stairs and other means of egress would require occupant sensors [C405.2.1.4 of the stretch code], which are currently excepted from Lighting Control provisions per C405.2. This change was actually standard for jobs that followed ASHRAE 90.1 as a compliance path for previous code cycles. The city could modify this requirement to allow partial lights so photoluminescent egress strips can charge in high-rise buildings, which Exception 3 of 90.1-2013 9.1.1 currently permits by implication. (Sort of.)
- Electrical outlets in offices are now proposed to be on timers, with half of them shutting off after hours [C405.10 of the stretch code].
- Whole-building energy monitoring is being carried over as well, but its sub-metering requirements are not as stringent as its ASHRAE counterpart. C405.14 of the stretch code will require monitoring of each type of total building energy consumption, such as annual gas use, fuel oil, propane, steam, and hot water. However, there are exceptions for buildings less than 25,000 s.f. in area, and for residential buildings with less than 10,000 s.f. in “common area.”
- Maximum allowed lighting wattage per square foot (lighting power density, or LPD) is proposed to drop significantly across the board. For example, offices under building area method are being dropped from a maximum permitted wattage of 0.82 watts per square foot to 0.69. Retail is being dropped from 1.26 to 0.91. Under the space-by-space method, things aren’t any easier, with open plan offices dropping from 0.90 watts per square foot to 0.78 and open sales areas are decreasing from 1.30 to 1.06.
We’ll be keeping an eye on the state stretch code as it moves towards enactment to see what 2019 will bring for the energy code. Stay tuned.