Main inspiration point: https://github.com/jcl5m1/ventilator/wiki/Build-a-Low-Cost-PAPR
For internal use only, not to be published publicly.
Total lung capacity is about 6L and respiratory rate is in order of (depending on the age) 12 to 18 breaths per minute.
Average resting respiratory rates by age are:
- birth to 6 weeks: 30–40 breaths per minute
- 6 months: 25–40 breaths per minute
- 3 years: 20–30 breaths per minute
- 6 years: 18–25 breaths per minute
- 10 years: 17–23 breaths per minute
- Adults: 12-18 breaths per minute[9]
- Elderly ≥ 65 years old: 12-28 breaths per minute.
- Elderly ≥ 80 years old: 10-30 breaths per minute.
Minimal flow rate for breathing is calculated to:
minimum: 6L * 12/min = 72 L/min maximum: 6L * 18/min = 108 L/min average: 90L/min
for good engineering measure we will multiply the average by 1.5
Desired flow rate: 135L/min
In accordance to European standard EN250:2000 Respiratory equipment.
Breathing pressure should be in range:
- Work of breathing: < 3.0 joules per litre
- Peak respiratory pressure: ±25 mbar (±2500 Pa) (inhalation or exhalation)
- Inhalation work of breathing: <0.3 joule per litre
- Pressure spikes with no measurable positive work of breathing: <10 mbar (1000 Pa)
- Pressure spikes with measurable positive work of breathing: <5 mbar (500 Pa)
- EURFILTER®
- EN 148
- STANAG 4155 (NATO)
- 3M™ EA/Case
- DIN 40mm
- Deprecated: 60mm used on Yugoslavian M1 gas mask
TODO: Find out more about each type because there are a lot of potential types
While breathing heavily through the EURFILTER® 7592/D filter, pressure was recorded using low tech method.
Apparatus consists of:
- (1) Mask EURMASK UNO
- (2) Filter EURFILTER® 7592/D
- (4) flexible silicone tube (any flexible tube will work)
- (5) straight glass tube (can be plastic, transparent)
- (6) water container
Pressure of about 16cmH2O (1569Pa or 15.7mbar) was recorded. That makes it outside the EN250 norm. But that is to be expected for heavy breathing.