501.4.3 Additions, Alterations, or Installations of Mechanical Systems in Existing Dwelling Units
1. If a dwelling unit was constructed after 2003 using the makeup air provisions of Section 501.4.2, makeup air quantity shall be determined by using IMC Table 501.4.1 and shall be supplied according to Section 501.4.2 when any of the following conditions occur:
1.1. A vented combustion appliance, including a solid fuel appliance, is installed or replaced.
1.2. An exhaust system is installed or replaced.
2. If a dwelling unit was constructed after 1999 using the provisions of the Minnesota Energy Code, Minnesota Rules, Chapter 7672, makeup air quantity shall be determined by using Table 501.4.1 and shall be supplied in accordance with Section 501.4.2 when any of the following conditions occur:
2.1. A vented combustion appliance, including a solid fuel appliance, is installed or replaced.
2.2. An exhaust system is installed or replaced.
3. When a solid fuel appliance is installed in a dwelling unit constructed during or after 1994 under the Minnesota Energy Code, Minnesota Rules, Chapter 7670, makeup air quantity shall be determined by using Table 501.4.1 and shall be supplied according to Section 501.4.2.
4. When an exhaust system with a rated capacity greater than 300 cfm (0.144 m3/s) is installed in a dwelling unit constructed during or after 1994 under the Minnesota Energy Code, Minnesota Rules, Chapter 7670, makeup air quantity shall be determined by using Table 501.4.3(1) and shall be supplied according to Section 501.4.2.
5. When an exhaust system with a rated capacity greater than 300 cfm (0.144 m3/s) is installed in a dwelling unit constructed prior to 1994, makeup air quantity shall be determined by using Table 501.4.3(2) and shall be supplied according to Section 501.4.2.
6. When a solid fuel appliance is installed in a dwelling unit constructed prior to 1994, makeup air quantity shall be determined by using Table 501.4.3(3) and shall be supplied according to Section 501.4.2.
1. A test is performed according to ASTM Standard E1998-02, Standard Guide for Assessing Depressurization-Induced Backdrafting and Spillage from Vented Combustion Appliances, and documentation is provided that the vented combustion appliances continue to operate within established parameters of the test.
2. A test approved by the building official verifies proper operation of vented combustion appliances.
TABLE 501.4.3(1)
PROCEDURE TO DETERMINE MAKEUP AIR QUANTITY FOR EXHAUST APPLIANCES IN EXISTING DWELLING UNITS
(Refer to Item 4 in Section 501.4.3 to determine applicability of this table)
| ONE OR MULTIPLE POWER VENT OR DIRECT VENT APPLIANCES OR NO COMBUSTION APPLIANCESA | ONE OR MULTIPLE FAN- ASSISTED APPLIANCES AND POWER VENT OR DIRECT VENT APPLIANCESB | ONE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCE OR ONE SOLID FUEL APPLIANCEC | MULTIPLE APPLIANCES THAT ARE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCES OR SOLID FUEL APPLIANCESD | |
| 1. Use the appropriate column to estimate house infiltration | ||||
| a) pressure factor (cfm/sf) | 0.15 | 0.09 | 0.06 | 0.03 |
| b) conditioned floor area (sf) Estimated House Infiltration (cfm): [1a × 1b] | — | — | — | — |
| 2. Exhaust capacity | ||||
| 80% of exhaust rating = exhaust capacity (cfm): | — | — | — | — |
| (not applicable if recirculating system or if powered makeup air is electrically interlocked and matched to exhaust) | ||||
| 3. Makeup air requirement | ||||
| a) Exhaust capacity (from above) | — | — | — | — |
| b) Estimated House Infiltration (from above) | — | — | — | — |
| Makeup air quality (cfm): [3a - 3b] | — | — | — | — |
| (if value is negative, no makeup air is needed) | ||||
| 4. For makeup air opening sizing, refer to Table 501.4.2 | ||||
| A. Use this column if there are other than fan-assisted or atmospherically vented gas or oil appliances or if there are no combustion appliances. |
| B. Use this column if there is one fan-assisted appliance per venting system. Other than atmospherically vented appliances may also be included. |
| C. Use this column if there is one atmospherically vented (other than fan-assisted) gas or oil appliance per venting system or one solid fuel appliance. |
| D. Use this column if there are multiple atmospherically vented gas or oil appliances using a common vent or if there are atmospherically vented gas or oil appliances and solid fuel appliances. |
TABLE 501.4.3(2)
PROCEDURE TO DETERMINE MAKEUP AIR QUANTITY FOR EXHAUST APPLIANCES IN EXISTING DWELLING UNITS
(Refer to Item 5 in Section 501.4.3 to determine applicability of this table)
| ONE OR MULTIPLE POWER VENT OR DIRECT VENT APPLIANCES OR NO COMBUSTION APPLIANCESA | ONE OR MULTIPLE FAN- ASSISTED APPLIANCES AND POWER VENT OR DIRECT VENT APPLIANCESB | ONE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCE OR ONE SOLID FUEL APPLIANCEC | MULTIPLE APPLIANCES THAT ARE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCES OR SOLID FUEL APPLIANCESD | |
| 1. Use the appropriate column to estimate house infiltration | ||||
| a) pressure factor (cfm/sf) | 0.25 | 0.15 | 0.10 | 0.05 |
| b) conditioned floor area (sf) | — | — | — | — |
| (including unfinished basements) | ||||
| Estimated House Infiltration (cfm): [1a × 1b] | — | — | — | — |
| or Alternative calculation (by using blower door test)E | ||||
| c) conversion factor | 0.75 | 0.45 | 0.30 | 0.15 |
| d) CFM50 value (from blower door test) | — | — | — | — |
| Estimated House Infiltration (cfm): [1c x 1d] | — | — | — | — |
| 2. Exhaust Capacity | ||||
| 80% of exhaust rating = exhaust capacity (cfm): | — | — | — | — |
| (not applicable if recirculating system or if powered makeup air is electrically interlocked and matched to exhaust) | ||||
| 3. Makeup air requirement | ||||
| a) Exhaust capacity (from above) | — | — | — | — |
| b) Estimated House Infiltration (from above) | — | — | — | — |
| Makeup air quality (cfm): [3a - 3b] | — | — | — | — |
| (if value is negative, no makeup air is needed) | ||||
| 4. For makeup air opening sizing, refer to Table 501.4.2 | ||||
| A. Use this column if there are other than fan-assisted or atmospherically vented gas or oil appliances or if there are no combustion appliances. |
| B. Use this column if there is one fan-assisted appliance per venting system. Other than atmospherically vented appliances may also be included. |
| C. Use this column if there is one atmospherically vented (other than fan-assisted) gas or oil appliance per venting system or one solid fuel appliance. |
| D. Use this column if there are multiple atmospherically vented gas or oil appliances using a common vent or if there are atmospherically vented gas or oil appliances and solid fuel appliances. |
| E. As an alternative, the Estimated House Infiltration may be calculated by performing a blower door test and multiplying the conversion factor by the CFM50 value. |
TABLE 501.4.3(3)
PROCEDURE TO DETERMINE MAKEUP AIR QUANTITY FOR EXHAUST APPLIANCES IN EXISTING DWELLING UNITS
(Refer to Item 6 in Section 501.4.3 to determine applicability of this table)
| ONE OR MULTIPLE POWER VENT OR DIRECT VENT APPLIANCES OR NO COMBUSTION APPLIANCESA | ONE OR MULTIPLE FAN- ASSISTED APPLIANCES AND POWER VENT OR DIRECT VENT APPLIANCESB | ONE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCE OR ONE SOLID FUEL APPLIANCEC | MULTIPLE APPLIANCES THAT ARE ATMOSPHERICALLY VENTED GAS OR OIL APPLIANCES OR SOLID FUEL APPLIANCESD | |
| 1. Use the appropriate column to estimate house infiltration | ||||
| a) pressure factor (cfm/sf) | 0.25 | 0.15 | 0.10 | 0.05 |
| b) conditioned floor area (sf) | — | — | — | — |
| (including unfinished basements) | ||||
| Estimated House Infiltration (cfm): [1a × 1b] | — | — | — | — |
| or Alternate calculation (by using blower door test)E | ||||
| c) conversion factor | 0.75 | 0.45 | 0.30 | 0.15 |
| d) CFM50 value (from blower door test) | — | — | — | — |
| Estimated House Infiltration (cfm): [1c × 1d] | — | — | — | — |
| 2. Exhaust capacity | ||||
| a) clothes dryer (cfm) | 135 | 135 | 135 | 135 |
| b) 80% of largest exhaust rating (cfm): | — | — | — | — |
| (not applicable if recirculating system or if powered makeup air is electrically interlocked and matched to exhaust) | ||||
| c) 80% of next largest exhaust rating (cfm) | Not applicable | — | — | — |
| (not applicable if recirculating system or if powered makeup air is electrically interlocked and matched to exhaust) | ||||
| Total Exhaust Capacity (cfm): [2a+2b+2c] | — | — | — | — |
| 3. Makeup air requirement | ||||
| a) Total Exhaust Capacity (from above) | — | — | — | — |
| b) Estimated House Infiltration (from above) | — | — | — | — |
| Makeup air quality (cfm): [3a - 3b] | — | — | — | — |
| (if value is negative, no makeup air is needed) | ||||
| 4. For makeup air opening sizing, refer to Table 501.4.2 | ||||
| A. Use this column if there are other than fan-assisted or atmospherically vented gas or oil appliances or if there are no combustion appliances. |
| B. Use this column if there is one fan-assisted appliance per venting system. Other than atmospherically vented appliances may also be included. |
| C. Use this column if there is one atmospherically vented (other than fan-assisted) gas or oil appliance per venting system or one solid fuel appliance. |
| D. Use this column if there are multiple atmospherically vented gas or oil appliances using a common vent or if there are atmospherically vented gas or oil appliances and solid fuel appliances. |
| E. As an alternative, the Estimated House Infiltration may be calculated by performing a blower door test and multiplying the conversion factor by the CFM50 value. |